The traditional answer to Peter’s question was 3x, so Peter may have felt he was being generous in suggesting 7x, but the implication of Jesus’ reply is that we must do away with all such limits and calculations. The reason is made clear in the parable that follows.
Ten thousand talents is an astronomical debt – we are talking millions of pounds in today’s money. For all the servant’s pleading that he would ”pay back everything”, clearly the debt could never be repayed, even in many lifetimes. With extraordinary grace, the master takes pity and cancels the entire debt. What a picture of the forgiveness shown us in Christ!
The second servant’s debt is utterly trivial in comparison, and so the lack of mercy in response to an almost identical plea (compare v.29 with v.26) is shown to be all the more inexcusable. Now the king, who had forgiven so generously, shows that he will also punish ruthlessly those who refuse to forgive.
The lesson is spelt out in v.35: those who will not forgive will not themselves be forgiven – the consequences of which, in the light of our indebtedness, are terrifying (see v.34). If the church is the community of the forgiven, then forgiveness must surely mark all our relationships. A forgiveness that is no mere form of words, because Jesus ends by saying it must be “from the heart” (v.35). That might well be hugely difficult, but clearly such forgiveness should flow from an appreciation of our own forgiven-ness.