What does forgive us your debts as you also have forgiven your debtors mean?

This is a verse of the "Lord's Prayer," spoken by Jesus when asked by his apostles for the correct way to pray to God. It can be found in the Gospel of Matthew 6:9-13. There are several possible translations-- the verse about "debt" and "debtors" is translated as "our trespasses" and "those who trespass against us" in some other versions. But the meaning is this: Jesus reminded his followers that God would forgive them for their mistakes, but they had to also show forgiveness to their fellow human beings.

So, using the debts and debtors metaphor, God will forgive our debts (what we owe to Him), but we have to also emulate that behavior by forgiving those who owe us. (Note, this does not necessarily mean that if someone owes you money, you are supposed to just forget it. It means you are not supposed to hold a grudge or try to make the debtor feel guilty. As God has been compassionate to you, go and be compassionate to others.)