The 2nd century model: Christ as Teacher
In the second and third century AD, by far the most dominant model of the atonement was Christ as a teacher of righteousness. Jesus through his life and teachings demonstrated, exemplified and taught a 'new law' of righteousness. We, by following his teachings and example can become righteous before God.
“At times, in all these writers [the Apostolic Fathers], the saving efficacy of Christ’s work is made to consist mainly – sometimes wholly – in His teaching.” (Hastings Rashdall, The Idea of Atonement in Christian Theology, pg 198)
“When we analyse their [the Apostolic Fathers'] utterances, we find that their chief emphasis is on what Christ has imparted to us – new knowledge, fresh life, immortality, etc” (J.N.D. Kelly, Early Christian Doctrines [revised edition], pg 163)
“We have already noted the popularity of the conception of redemption as enlightenment among the Apostolic Fathers. It reappears in the Apologists…” (Kelly, 169)
“[In the Apologists] his chief vocation as Savior was to teach men the truth about monotheism and the moral life.” (Jaroslav Pelikan, The Emergence of the Catholic Tradition 100-600AD, 153)
“Undoubtedly the principal purpose of the incarnation… strikes him [Justin Martyr] as having been didactic. Having forgotten the truth and having been inveigled into ignorance and positive error by the demons, men desperately need the restoration of the light they have lost. As ‘the new law giver’ or again, ‘the eternal, final law, the faithful covenant which replaces all laws and commandments’ , Christ imparts this saving knowledge. It was to bestow such illumination, in particular the realization of the oneness of God and the belief in the moral law, and to restore men by it, that the Logos in fact became man .” (Kelly, 168-169)
“there is a distinct tendency in Tertullian to reduce Christ’s achievement to ‘the proclamation of a new law and a new promise of the kingdom of heaven’, and to represent Him as ‘the illuminator and instructor of mankind’.” (Kelly, 177)
“[Clement of Alexandria's] most frequent and characteristic thought is that Christ is the teacher Who endows men with true knowledge, leading them to a love exempt from desires and a righteousness who prime fruit is contemplation.” (Kelly 183)
“Clement is equally fond of speaking of Christ as the Teacher and the Saviour. And the two words mean for him much the same thing, for it is mainly by His teaching and His influence that Christ saves.” (Rashdall, 225)
“[For Origen, Christ] is ‘the pattern of the perfect life’, the exemplar of true virtue into Whose likeness Christians are transformed, thereby being enabled to participate in the divine nature.” (Kelly, 184)
“[Hippolytus'] most characteristic thought, however, is one derived from the Apologists, viz. that the redemption chiefly consists in the knowledge of God mediated by the Word through nature and history, the law and the prophets, and finally the Gospel: ‘appearing in the world as the truth, He taught the truth.’” (Kelly, 178)
Thus, in summary:
“it is clear that meditation on the life and teachings of Jesus was a major preoccupation of the piety and doctrine of the Church [of the second century].... Christ as example and Christ as teacher were constant and closely related doctrinal themes.... [A common teaching was] salvation through the obedience to the teachings of Christ and through imitation of his example.... the work of Christ was represented as that of the exemplar and teacher who brought the true revelation of God’s will for man.” (Pelikan, 142-152)
PS. If anyone can recommend any good books on second and third century atonement theology I'd be interested to hear.