What Peter asked of the Lord was reasonable. What the Lord said to Peter seems so unreasonable, doesn't it?
"He has forgiven you, so also forgive all those who do you wrong. "How long am I to do that?' one would ask. 'I would not mind doing it three or four times.'
There was one of old who would go the length of six or seven, but Jesus Christ said 'unto seventy times seven.' That is a very considerable number. You may count whether you have yet reached that amount, and if you have, you will now be glad to begin again, still forgiving, even as God for Christ's sake has forgiven you."
"Lord, how often shall my brother sin against me and I forgive him? Up to seven times?" Jesus said to him, "I do not say to you, up to seven times, but up to seventy times seven." Matthew 18:21-22
"All our transgressions are swept away at once...and so completely removed from us that no guilty trace of them remains. They are all gone!... Sins against a holy God, sins against His loving Son, sins against the gospel as well as against the law, sins against man... sins of the body as well as sins of the mind, sins as numerous as the sands on the seashore and as great as the sea itself: All, all are removed from us...
All this evil was rolled into one great mass and laid upon Jesus, and having borne it all, He has made an end of it forever. When the Lord forgave us, He forgave us the whole debt...He did not take the bill and say, 'I strike out this item and that,' but the pen went through it all: PAID. It was a receipt in full of all demands; Jesus took the handwriting that was against us and nailed it to His cross, to show before the entire universe that its power to condemn us had ceased forever. We have in Him a full forgiveness."