Matthew 6:15

15 But if you do not forgive others their sins, your Father will not forgive your sins.

Read Matthew 6:15 Using Other Translations

But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.
but if you do not forgive others their trespasses, neither will your Father forgive your trespasses.
But if you refuse to forgive others, your Father will not forgive your sins.