Be on your guard! If another disciple sins, you must rebuke the offender, and if there is repentance, you must forgive. And if the same person sins against you seven times a day, and turns back to you seven times and says, ‘I repent,’ you must forgive” (Luke 17:3-4)
We say a great many things in church (and out of church too) without thinking of what we are saying. For instance, we say in the Creed “I believe in the forgiveness of sins.” I had been saying it for several years before I asked myself why it was in the Creed.