Commenting on “forgive us our debts as we forgive our debtors” in the Lord’s Prayer:

Wrapt up in its encouragement there is a check to conscience. We are not to be allowed to present the petition at all, unless it be from the deepest sense of our need, and of the greatness of the gift we seek; a sense which is in reality equivalent to true repentance, and which brings with it, as its uniform and necessary fruit, love to our neighbor. And every one who knows how apt we are to become either hypocrites or careless formalists in prayer, will recognize the suitableness of such a check, and will appreciate the propriety of its being appended to this petition rather than any other. For this, more than any other, has been a lip-deep petition, and has been shamefully abused by self-satisfied or careless petitioners, by ourselves when we ask forgiveness, as we often ask it, without any considerate remembrance of the cost of it, thinking it the easiest thing for God to give, and forgetting that this has been prepared for us at a far greater expense, at a more personal expense, than anything else we can implore. It has been the endeavor of many teachers to persuade us, and yet we need to be reminded, that a word could create and beautify a world, and “an act of will bestow it upon us,” but it has cost God the humiliation and suffering of His well-beloved Son to grant the boon which now we ask. And therefore we are here suddenly startled out of all dreamy and indifferent prayer, and are aroused by being brought face to face with our own real desires and our own real life; we are reminded that our prayer had far better be unsaid, if it is not of a piece with our state of heart; that we cannot pray as one person and live as another; that we do not look as earnestly as we ought for the remission of our debts, (and therefore need not expect it,) unless we be doing what we can to avoid contracting new ones; that, in short, we have no encouragement whatever to present this petition, unless conscience assures us that the love of God, on which we hope, has entered our souls and changed them, and has become the principle and law of our lives.

Emphasis mine: Marcus Dods, The Prayer That Teaches to Pray