Certain traditions and denominations teach the possibility of Christian perfection, including the Catholic Church, where it is closely associated with consecrated life. It is also taught in Methodist churches and the holiness movement, in which it is sometimes termed Wesleyan perfectionism. Other denominations, such as the Lutheran and Reformed churches, reject teachings associated with Christian perfection as contrary to the doctrine of salvation by faith alone.
The terms "perfect" and "perfection" are drawn from the Greek teleios and teleisis, respectively. The root word, telos, means an "end" or "goal". In contemporary translations, teleios and teleisis are often rendered as "mature" and "maturity", respectively, so as not to imply infallibility or the absence of defects. Rather, in the Christian tradition, teleisis has referred to progressing towards spiritual wholeness or health.
In antiquity, baptism was commonly referred to as the perfecting of the Christian. This view was expressed by Clement of Alexandria in his work Paedagogus: "Being baptized, we are illuminated; illuminated we become children [lit. sons]; being made children, we are made perfect; being made perfect, we are immortal." In another work, the Stromata, Clement discussed three stages in Christian life that led to a more mature perfection. The first stage was marked by the change from heathenism to faith and initiation into the Christian religion. The second stage was marked by a deeper knowledge of God that resulted in continuing repentance from sin and mastery over the passions (apatheia). The third stage led to contemplation and agape love. Origen also proposed his own stages of spiritual ascent beginning with conversion and ending with perfect union with God in love.
Gregory of Nyssa defined human perfection as "constant growth in the good". For Gregory, this was brought about by the work of the Holy Spirit and the selfdiscipline of the Christian. Pseudo-Macarius taught that inner sin was rooted out of the pure in heart, but he also warned against the hidden potential for sin in everyone so that no one should ever say, "Because I am in grace, I am thoroughly freed from sin." By the 4th century, the pursuit of the life of perfection was identified with asceticism, especially monasticism and withdrawal from the world.
In the 12th century, Bernard of Clairvaux developed the idea of the ladder of love in his treatise, On the Love of God. This ladder had four rungs or degrees. The first and lowest degree was love of self for self. The second degree was love of God for what he gives. The third degree was love of God for his own sake; it would not be difficult, according to Bernard, for those who truly loved God to keep his commandments. The fourth degree was love of self only for God's sake; it was believed that this degree of perfection in love was only rarely achieved before death.
Thomas Aquinas wrote of three possible levels of perfection. The first, absolute perfection, is where God is loved as much as he can be loved; only God himself can be this perfect. The second level, where love for God fills a person constantly, is possible after death but not in life. The lowest level of perfection was thought to be possible to achieve while living. Theologian Thomas Noble, Professor of Theology at Nazarene Theological Seminary, Kansas City, described Aquinas' view of this level of perfection as follows:
All Christians have the grace of caritas infused into them at baptism and this love for God excludes all mortal sins. Such sins are not impossible, and, if committed, require the grace of penance, but Christians do not live committing flagrant acts of intentional sin contrary to their love for God. That is incompatible with the state of grace. But those who are no longer beginners, but making progress in the life of perfection, come to the point where everything contrary to being wholly in love with God is excluded: they love God with all their hearts.