18 “And lead us not into temptation. Forgive us our debts, as we also forgive our debtors,” we say because of past sins, which we cannot undo, that they should not have been done. You can labour not to do what you have done before, but how can you bring about, that that which you have done should not be done? As regards those things which have been done already, that sentence of the prayer is your help, “Forgive us our debts, as we also forgive our debtors.” As regards those into which you may fall, what will you do? “Lead us not into temptation, but deliver us from evil.” “Lead us not into temptation, but deliver us from evil,” that is, from temptation itself.
Source: Sermons on Selected Lessons of the New Testament (New Advent)