forgive and forget
Both pardon and hold no resentment concerning a past event. For example, After Meg and Mary decided to forgive and forget their differences, they became good friends. This phrase dates from the 1300s and was a proverb by the mid-1500s. For a synonym, see let bygones be bygones.
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.