From the beginning there has been a stream of Christian moral thinking which has expected Christians not to sin and has believed in their capacity and potentiality to avoid it altogether. It is problematic to demand of human beings a personal standard of morality which is in practice unattained. The difficulty was already felt by the great Stoic moralists, Seneca and Epictetus. Perhaps any moral code worthy of commanding the allegiance of serious minds is one beset by the hardness of the ideal's practicability. But it is easy to think of a minimum standard as being commanded, and of higher ideals as being a counsel of perfection, by which impracticability for all but rare individuals is normally meant. The ascetic movement of the fourth century was a quest for perfection. Jesus' words in the Sermon on the Mount (Matt. 5: 48) 'Be perfect as your Father in heaven is perfect' prescribed some such ideal. His words to the rich young ruler (Matt. 19: 21, not in Mark's telling of the same story) 'If you aspire to be perfect, sell what you have and give to the poor' have obviously had huge influence in bequeathing the distinction between precept and counsel.
The absoluteness of the vows undertaken at baptism commits the believer to follow Christ in keeping to the path of a good moral life. But the frailty of human nature constantly leads to failures, and the question arose very early in the development of the Church: what ought to be done to restore the penitent and to exclude the impenitent and mocking apostate as long as their mind does not seriously change?
Jesus was understood to have entrusted the forgiving of believers' sins to the Church (Matt. 18: 15-17); in the last resort, one unwilling to heed the community's admonition is to be treated as an outsider and a heathen. The community is given power to 'bind and loose', and this is expressly said in the sense that decisions on earth have consequences in heaven. In John 20: 21-3 this power and duty are entrusted to the apostles. In Matt. 16: 19 the power of the keys is entrusted to Peter. In the first century it was a general axiom that reconciliation with the Church is the path to reconciliation with God and vice versa. At Rome late in the fourth century Ambrosiaster (Quaestiones, 102, CSEL 50) took it for granted that if a sin has not been absolved on earth, it remains on the debit side in heaven. In the third