Conversion to Christianity is the religious conversion of a previously non-Christian person to some form of Christianity. It has been called the foundational experience of Christian life. Conversion to Christianity primarily involves belief (faith) in the Christian God, wherein one notices that one has fallen short of God's image in what he created man after which was in his love, glory, and holiness, repentance of sin, and confession of their belief that Jesus Christ is the Son of God and the all-sufficient and only means by whom one's sin can be atoned for and therefore the only route to salvation. While conversion to Christianity may simply involve a personal choice to identify with Christianity rather than with another religion, many Christians understand it to mean that the individual attains eternal salvation by a genuine conversion experience or act—a "radical transformation of self."
Conversion has also been described as the point of transition from "natural life" to spiritual life. In this sense it is seen as both a "radical change of heart and life" and also a more gradual process in which the convert's spiritual nature develops through Christian culture and education. According to theologian Charles Curran, conversion is the central moral message of Jesus. Curran describes it as an "awakening to a consciousness of the presence of divine reality" in one's life. The Gospel of Matthew quotes Jesus as teaching, "Truly I say to you, unless you are converted and become like children, you will not enter the kingdom of heaven."
Social scientists have shown great interest in the Christian conversion as a religious experience that believers describe as strengthening their faith and changing their lives.Christianization, defined as the "reformulation of social relations, cultural meanings, and personal experience in terms of (commonly accepted or supposed) Christian ideals," should be distinguished from conversion. Christianization is the broader cultural term, and typically has involved efforts to systematically convert an entire continent or culture from existing beliefs to Christianity.