We are products not only of our own decisions, but also of the culture in which we live. American evangelicalism has a particular culture that affects its relationship with contemporary concepts of spiritual formation, and it may be useful to consider that culture and some of its historical roots so as to understand how and why the movement reacts to formational ideas. A full such examination would surely take up an entire volume, so large amounts of detail will need to be omitted for this short essay, but hopefully this will provide some relevant points to be aware of.
Of course, evangelicalism is notoriously difficult to define and set boundaries around. Even evangelicals do not always agree who is considered evangelical, and entire denominations can be uncertain and split on the matter of their own relationship to it. Different denominations and groups that could potentially fall under the title have had vastly different histories, experiences, ideas, and practices. To clarify my intention, I am specifically considering those evangelicals who are theologically conservative American Protestants whose historic roots at least partially go through early 20th century fundamentalism or a parallel ideology (such as Southern Baptists).
Moreover, spiritual formation can likewise be difficult to define. I am particularly considering the late 20th and 21st century movement in American Protestantism that focuses on the sanctification of believers through reintegration with historic (pre-Reformation) Christianity, the practice of specific disciplines, the integration of psychological ideas into theological and spiritual context, and/or the exploration of contemplative or mystical practices and experiences. Any given instance of spiritual formation need not include all of these elements, but it must extend beyond theological or biblical knowledge and also training for life and ministry that is often called “discipleship”.
Fundamentals of Evangelical Spirituality
When discussing evangelicalism, it is nigh impossible to escape the work of David Bebbington whose “quadrilateral” has become the de facto standard description, though not definition, of the movement. He asserts four elements: biblicism, an emphasis on the Bible; activism, a drive to accomplish something in the world; conversionism, an emphasis on the conversion experience; and crucicentrism, a focus on the cross that generally manifests as a particular stance on the atonement. Each of these is applicable to evangelical spirituality, though perhaps differently emphasized and expressed throughout its history.
Biblicism has perhaps changed the least, having been established in the Reformation with the slogan, sola scriptura. Evangelical spirituality is marked by turning to the Bible for inspiration and truth. For some, the Bible has become the only source of truth for matters that have a spiritual element while others see it as more of a plumb line against which all other sources of truth must be measured. Those with the former perspective are direct descendents of early 20th century fundamentalists who opposed modernism's incursion into theology, while many of the latter stem from mid-20th century neo-evangelicalism, which sought to broaden evangelicals' relationship with the world. Regardless of which stream one examines, one of the most recurrent expressions of evangelical spirituality has been the daily quiet time in which one dedicates time to read and potentially pray over scripture.
"Since many spiritual formation writers draw from sources beyond Scripture, sometimes from Roman Catholic thought, their formation ideas can be resisted by evangelicals who hold interpretations from Reformation perspectives."
The character of activism has changed throughout history, but essentially only moving between two perspectives. Early evangelicalism tended to hold to a postmillennial theology, expecting that Protestants would be capable of transforming the world for good and thereby ushering in Christ's millennial reign. This spurred on what might now be called social justice, including actions like the establishment of hospitals and the abolition of slavery in Britain.
However, two factors changed this significantly. With the Civil War and later immigration of seemingly less civilized peoples, American evangelicals could no longer see the idea of making the world holy as feasible. In response they largely turned to J. N. Darby's solution of premillennial dispensationalism. Dispensationalism implied that the world would turn continually more evil until Jesus returned to set it aright, and with the seemingly great evil all around them, evangelicals began expecting Jesus' imminent return. Additionally, the fundamentalist-modernist controversy arose as some theologians increasingly attempted to integrate modern ideas into their work. Fundamentalism sharply disagreed with this practice, but society declared modernism the victor as seen most publicly in the results of the so-called Scopes Monkey Trial. Fundamentalists responded by separating themselves from the wider culture and creating their own subculture.
Both of these issues changed the primary character of evangelical activism from social action to proselytizing. Jesus' imminent return made conversion crucial as soon as possible and earthly matters unimportant in comparison. Similarly, their isolationism made it more difficult to do any good for others until those others had been brought into the fold through evangelism. The fundamentalist-modernist debate exacerbated this given that modernists became associated with the social gospel and fundamentalists shunned anything that might be mistaken for liberal theology. Social action became highly suspect.
Neo-evangelicalism has allowed contemporary evangelicals to re-blend these forms of activism, but it is rare to see social action without some drive toward evangelization, particularly with the evangelical distinction of conversionism. Evangelicalism was born through the revivals of the early 18th century, which set the tone for conversion to remain important throughout its spiritual history. During fundamentalism, the importance of this element became magnified due to the sense that Christ would return at any moment as well as what might be called supernaturalism. Supernaturalism was another reaction against the modernists' attempt to integrate contemporary, naturalistic ideas into their theology. Fundamentalists responded by emphasizing the spiritual dimension, which evolved into supernatural solutions to all sins and struggles. One's conversion became the key moment when God's power intersected with the believer, and thus it became seen as the instrument through which all of one's difficulties were relieved, if only one possessed sufficient faith. All that one needed, it was determined, was provided at conversion, so evangelical spirituality began to focus on not only creating converts, but also memorializing one's conversion through testimonies and the remembrance of it for the purpose of strengthening one's faith and gaining power over sin.
"Fundamentalism and dispensationalism's strong emphasis on conversion as the lynchpin of the Christian life can also make spiritual formation difficult to accept."
Crucicentrism in the contemporary era goes along with this more fundamentalist conception of conversion. The reason that conversion has power is because of God's work at the cross, and therefore one memorializes not only one's conversion, but even more the crucifixion and resurrection. Everything that is necessary, it is argued, occurred at Calvary, and therefore evangelical spirituality revolves around it, sometimes to the exclusion of what is happening in the present. 
Resistance to Spiritual Formation
Certain aspects of evangelicalism's history can be seen as hindrances to the contemporary understanding of spiritual formation. The fundamentalist interpretation of the Reformation's sola scriptura, seeing the Bible as the only source of truth for life, can regard extra-biblical ideas on dealing with sin and behavior as suspect or anathema. Similarly, sola fide has at times been interpreted by fundamentalists and those of both Lutheran and Reformed heritage as meaning that any action taken to develop as a Christian is works-righteousness. Also stemming from the Reformation is the representation of Roman Catholicism as heretical, if not of the antichrist, and therefore antagonistic to Christianity. Since many spiritual formation writers draw from sources beyond Scripture, sometimes from Roman Catholic thought, and because they often encourage particular disciplines and practices, their formation ideas can be resisted by evangelicals who still hold these interpretations of Reformation perspectives.
It is also potentially worth noting that evangelicalism has always been a religion for the common man, sometimes even referred to as “America's Folk Religion.” The early revivals drew crowds of ordinary people, and its organizers aimed at reaching and mobilizing those people. While this is not a bad thing, it can carry with it an avoidance of complexity, but spiritual formation can have aspects that defy common sense and a simplistic understanding of God and the human person. Evangelicals can reject anything complex or counter-intuitive and therefore reject spiritual formation on these grounds.
"Not everything in evangelicalism's history predisposes it to reject spiritual formation. The contemporary spiritual formation movement could be likened to movements in Protestantism including Puritanism and Pietism."
Like fundamentalism, the Second Great Awakening changed the way that conversion was understood. For much of church history, conversion was part of a long process that included growing holiness, but figures in these revivals such as Phoebe Palmer stressed an immediate decision and suggested that one could be sanctified completely at the same moment as one was justified. Not all of evangelicalism agreed with this modification of Wesleyan thought, but some erosion of the importance of sanctification as a process occurred. Even those who did not agree with the idea of entire sanctification still came to stress the importance of conversion in a single moment, which has dominated evangelical spirituality for perhaps two centuries.
J. I Packer asserts that Keswick spirituality, which originated from late 19th century UK conventions of the same name, has come to dominate evangelical thought on sanctification , and this mentality also hinders acceptance of spiritual formation. Keswick spirituality was an effort to create a middle ground between a Reformed overemphasis on morality through willpower and the Holiness idea of perfection being divinely granted to the mature Christian. The idea could be perhaps best summarized by constant surrender: the Christian could become free from sin at each moment through the power of the Holy Spirit so long as the person surrendered to God continually. It was admitted that every Christian would occasionally fail, thereby eliminating the possibility of sinless perfection. It also allowed for an explanation for the occurrence of sin: a failure to surrender one’s will to God in that moment. This implies that character or heart formation is far less important among evangelicals than is the strengthening of the will. One is not formed over time, but instead needs to simply but constantly “give it all to Jesus”.
Fundamentalism and dispensationalism's strong emphasis on conversion as the lynchpin of the Christian life can also make spiritual formation difficult to accept. If Jesus could return at any moment, this leaves little time for formation. Time dedicated to personal growth becomes selfish in light of the neediness of the unbelieving masses. Likewise, if Jesus provided all that is necessary at the cross, then all that a person needs was already obtained at the moment of salvation; sanctification is already finished if only the believer would take hold of it.
Moreover, fundamentalism became focused on doctrinal defense against the modernists, a doctrinal stress that today emphasizes biblical and systematic theology for the scholar and apologetics for the layman. For both, the intellect is dedicated more to “rightly dividing the word of truth” than to determining how to live well and righteously.
The integration of charismatic elements into evangelicalism could also become a hindrance, as its Pentecostal roots stress the Holy Spirit's role in empowering the believer instantaneously. The Spirit's slower, more gradual, and at times more subtle work was eclipsed by manifestations of power and signs. While Pentecostalism and spiritual formation are not antithetical, their different emphases can complicate matters.
Historical Roots of Hope
This is not to say that everything in evangelicalism's history predisposes it to reject spiritual formation. Indeed, the contemporary spiritual formation movement could potentially be likened to previous movements in Protestantism including Puritanism and Pietism. Puritanism was a movement within and eventual break from the Anglican church that focused in part on godliness in everyday life. Pietism was a later movement within Lutheranism that strove to reignite the people's passion for holiness in the midst of churches splitting doctrinal hairs and ignoring the laypeople. Further, it cannot be ignored that evangelicalism was born in revivalism and therefore has its origins in a passion for being transformed by God.
Indeed, much of Protestantism views spirituality as primarily about sanctification as evidenced by the fact that they were historically more likely to call it piety or holiness, shunning “spirituality” as a Roman Catholic term. Even if movements such as Keswick spirituality have provided an untenable view of it, sanctification, in some form, has always been a major concern of evangelicals. Prior to the Second Great Awakening, as previously noted, the understanding of conversion generally included a process of gradual growth in knowledge and godliness, and it is not outside of the bounds of possibility for a modified ideology to be revived in the contemporary era.
"Neo-evangelicalism has broadened the realm of possibilities and acceptable perspectives, which opened the doors to the contemporary spiritual formation movement in the first place."
While fundamentalism may have largely made evangelicals suspicious of spiritual formation, neo-evangelicalism has broadened the realm of possibilities and acceptable perspectives, which opened the doors to the contemporary spiritual formation movement in the first place. Additionally, many neo-evangelical strains have become heavily pragmatic, as evidenced by the preponderance of books and sermons on topics such as developing a good marriage. While much of this is simplistic or rigid, that practicality could form the roots from which a more substantial understanding of practical formation might flourish.
I have had no space to discuss Wesleyanism, historical Reformed perspectives on sanctification, or a number of other potentially relevant matters, but hopefully this is sufficient to provide an understanding of some elements of evangelicalism's relationship to sanctification and spiritual formation. While there are aspects of its history that make it leery of spiritual formation's contemporary manifestation, formation also fits well within both Protestant and evangelical progression and pattern in history.
1 Crucicentrism also tends to manifest as a dedication to the penal-substitutionary theory of the atonement, but this is largely a theological point rather than an aspect of evangelical spirituality.
2 See J. I. Packer, Keep in Step with the Spirit (Old Tappan, NJ: F. H. Revel, 1984)