Verses with the word debt in the New Testament (4 verses):

Matthew 18:27
Then the lord of that servant was moved with compassion, and loosed him, and forgave him the debt.

Matthew 18:30
And he would not: but went and cast him into prison, till he should pay the debt.

Matthew 18:32
Then his lord, after that he had called him, said unto him, O thou wicked servant, I forgave thee all that debt, because thou desiredst me:

Romans 4:4
Now to him that worketh is the reward not reckoned of grace, but of debt.