And (even) this (He seeks), only that we may not become unprofitable, since even without this He could have freed us from them: but like as we (with the same view) devise and arrange many things for our servants to do, so does He in the matter of our salvation. “Let us anticipate His face with thanksgiving.”, since He is good and kind. But if you call not upon Him, what will He do? Thou dost not choose to say, Forgive; you will not say it from your heart, but with your mouth only.
What is it, to call in truth? (To call) with purpose of heart, with earnestness, with a sincere mind; just as men say of perfumes, “This is genuine, and has nothing spurious,” so here. He who truly calls on Him, he who truly prays to Him, continually attends to it, and desists not, until he obtain (his request): but he who does it in a merely formal manner (ἀ φοσιούμενος), and even this only by way of fulfilling a law, does not call in truth. Whosoever you are, say not only, “I am a sinner,” but be earnest also to rid yourself of this character; say not this only, but also grieve.
If you grieve, you are in earnest: if you are not in earnest, you grieve not: if you grieve not, you trifle. What sort of man is he who shall say, “I am sick,” and not to do all to be freed from his sickness? A mighty weapon is Prayer. “If you,” says the Lord, “know how to give good gifts to your children, how much more your Father?” Then wherefore are you unwilling to approach Him? He loves you, He is of more power than all besides. Both willing is He and able, what is there to hinder?
Nothing. But then, on our part, let us draw near with faith, draw near, offering the gifts that He desires, forgetfulness of wrongs, kindness, meekness. Though thou be a sinner, with boldness shall you ask of Him forgiveness of your sins, if you can show that this has been done by yourself: but though thou be righteous, and possess not this virtue of forgetfulness of injuries, you are none the better for it. It cannot be that a man who has forgiven his neighbor should not obtain perfect forgiveness: for God is beyond comparison more merciful than we.
What do you say? If you say, “I have been wronged, I have subdued my anger, I have endured the onset of wrath because of Your command, and dost Thou not forgive?” Full surely He will forgive: and this is plain to all. Therefore let us purge our soul from all resentment. This is sufficient for us, in order that we may be heard; and let us pray with watching and much perseverance, that having enjoyed His bountiful mercy, we may be found worthy of the good things promised, through the grace and mercy of our Lord Jesus Christ, with Whom to the Father, together with the Holy Spirit, be glory, might, honor, now and ever, world without end. Amen.
Source: Homilies on Acts (New Advent)