9. Then forasmuch as it comes to pass that we sin even after the washing of regeneration, He, showing His love to man to be great even in this case, commands us for the remission of our sins to come unto God who loves man, and thus to say,
"Forgive us our debts, as we also forgive our debtors."
Seest thou surpassing mercy? After taking away so great evils, and after the unspeakable greatness of His gift, if men sin again, He counts them such as may be forgiven. For that this prayer belongs to believers, is taught us both by the laws of the church, and by the beginning of the prayer. For the uninitiated could not call God Father. If then the prayer belongs to believers, and they pray, entreating that sins may be forgiven them, it is clear that not even after the laver is the profit of repentance taken away. Since, had He not meant to signify this, He would not have made a law that we should so pray. Now He who both brings sins to remembrance, and bids us ask forgiveness, and teaches how we may obtain remission and so makes the way easy; it is perfectly clear that He introduced this rule of supplication, as knowing, and signifying, that it is possible even after the font to wash ourselves from our offenses; by reminding us of our sins, persuading us to be modest; by the command to forgive others, setting us free from all revengeful passion; while by promising in return for this to pardon us also, He holds out good hopes, and instructs us to have high views concerning the unspeakable mercy of God toward man.
But what we should most observe is this, that whereas in each of the clauses He had made mention of the whole of virtue, and in this way had included also the forgetfulness of injuries (for so, that "His name be hallowed," is the exactness of a perfect conversation; and that "His will be done," declares the same thing again: and to be able to call God "Father," is the profession of a blameless life; in all which things had been comprehended also the duty of remitting our anger against them that have transgressed): still He was not satisfied with these, but meaning to signify how earnest He is in the matter, He sets it down also in particular, and after the prayer, He makes mention of no other commandment than this, saying thus:
"For if ye forgive men their trespasses, your heavenly Father also will forgive you."
So that the beginning is of us, and we ourselves have control over the judgment that is to be passed upon us. For in order that no one, even of the senseless, might have any complaint to make, either great or small, when brought to judgment; on thee, who art to give account, He causes the sentence to depend; and "in what way soever thou hast judged for thyself,  in the same," saith He, "do I also judge thee." And if thou forgive thy fellow servant, thou shalt obtain the same favor from me; though indeed the one be not equal to the other. For thou forgivest in thy need, but God, having need of none: thou, thy fellow slave; God, His slave: thou liable to unnumbered charges; God, being without sin. But yet even thus doth He show forth His lovingkindness towards man.
Since He might indeed, even without this, forgive thee all thine offenses; but He wills thee hereby also to receive a benefit; affording thee on all sides innumerable occasions of gentleness and love to man, casting out what is brutish in thee, and quenching wrath, and in all ways cementing thee to him who is thine own member.
For what canst thou have to say? that thou hast wrongfully endured some ill of thy neighbor? (For these only are trespasses, since if it be done with justice, the act is not a trespass.) But thou too art drawing near to receive forgiveness for such things, and for much greater. And even before the forgiveness, thou hast received no small gift, in being taught to have a human soul, and in being trained to all gentleness. And herewith a great reward shall also be laid up for thee elsewhere, even to be called to account for none of thine offenses.
What sort of punishment then do we not deserve, when after having received the privilege, we betray our salvation? And how shall we claim to be heard in the rest of our matters, if we will not, in those which depend on us, spare our own selves?
10. "And lead us not into temptation; but deliver us from the evil one: for Thine is the kingdom, and the power, and the glory, for ever. Amen."
Here He teaches us plainly our own vileness, and quells our pride, instructing us to deprecate all conflicts, instead of rushing upon them. For so both our victory will be more glorious, and the devil's overthrow more to be derided. I mean, that as when we are dragged forth, we must stand nobly; so when we are not summoned, we should be quiet, and wait for the time of conflict; that we may show both freedom from vainglory, and nobleness of spirit.
And He here calls the devil "the wicked one," commanding us to wage against him a war that knows no truce, and implying that he is not such by nature. For wickedness is not of those things that are from nature, but of them that are added by our own choice. And he is so called pre-eminently, by reason of the excess of his wickedness, and because he, in no respect injured by us, wages against us implacable war. Wherefore neither said He, "deliver us from the wicked ones," but, "from the wicked one;" instructing us in no case to entertain displeasure against our neighbors, for what wrongs soever we may suffer at their hands, but to transfer our enmity from these to him, as being himself the cause of all our wrongs.
Having then made us anxious as before conflict, by putting us in mind of the enemy, and having cut away from us all our remissness; He again encourages and raises our spirits, by bringing to our remembrance the King under whom we are arrayed, and signifying Him to be more powerful than all. "For Thine," saith He, "is the kingdom, and the power, and the glory."
Doth it not then follow, that if His be the kingdom, we should fear no one, since there can be none to withstand, and divide the empire with him. For when He saith, "Thine is the kingdom," He sets before us even him, who is warring against us, brought into subjection, though he seem to oppose, God for a while permitting it. For in truth he too is among God's servants, though of the degraded class, and those guilty of offense; and he would not dare set upon any of his fellow servants, had he not first received license from above. And why say I, "his fellow servants?" Not even against swine did he venture any outrage, until He Himself allowed him; nor against flocks, nor herds, until he had received permission from above.
"And the power," saith He. Therefore, manifold as thy weakness may be, thou mayest of right be confident, having such a one to reign over thee, who is able fully to accomplish all, and that with ease, even by thee.
"And the glory, for ever. Amen." Thus He not only frees thee from the dangers that are approaching thee, but can make thee also glorious and illustrious. For as His power is great, so also is His glory unspeakable, and they are all boundless, and no end of them. Seest thou how He hath by every means anointed His Champion, and hath framed Him to be full of confidence?
John Chrysostom (c.347-407): Homily 19 on St. Matthew's Gospel.