The song Seven Times Seven Times Seventy-seven is based on The Parable of the Unmerciful Servant in Matthew 18. The title of the song comes from Jesus response to a question from Peter.
Then Peter came to Jesus and asked, “Lord, how many times shall I forgive my brother or sister who sins against me? Up to seven times?” Jesus answered, “I tell you, not seven times, but seventy-seven times.
Matthew 18:21-22