Ps 42:1

“"Judge me, O Lord, and separate my cause from the ungodly nation." I do not dread Thy judgment, because I know Thy mercy. "Judge me, O God," he cries. Now, meanwhile, in this state of pilgrimage, Thou dost not yet separate my place, because I am to live together with the "tares" even to the time of the "harvest:" Thou dost not as yet separate my rain from theirs; my light from theirs: "separate my cause." Let a difference be made between him who believes in Thee, and him who believes not in Thee. Our infirmity is the same; but our consciences not the same: our sufferings the same; but our longings not the same. "The desire of the ungodly shall perish," but as to the desire of the righteous, we might well doubt, if He were not "sure" who promised. The object of our desires is He Himself, who promiseth: He will give us Himself, because He has already given Himself to us; He will give Himself in His immortality to us then immortal, even because He gave Himself in His mortality to us when mortal...”

“Sometimes judgment means punishment, sometimes it means discrimination. According to that mode of speech in which judgment means discrimination, "we must all appear before the judgment-seat of Christ that" a man "may there receive what things he has done in the body, whether it be good or ill." For this same is a discrimination, to distribute good things to the good, evil things to the evil. For if judgment were always to be taken in a bad sense, the psalm would not say, "Judge me, O God." Perhaps some one is surprised when he hears one say, "Judge me, O God." For man is wont to say, "Forgive me, O God;" "Spare me, O God." Who is it that says, "Judge me, O God"? Sometimes in the psalm this very verse even is placed in the pause, to be given out by the reader and responded by the people. Does it not perhaps strike some man's heart so much that he is afraid to sing and to say to God, "Judge me, O God"? And yet the people sing it with confidence, and do not imagine that they wish an evil thing in that which they have learned from the divine word; even if they do not well understand it, they believe that what they sing is something good. And yet even the psalm itself has not left a man without an insight into the meaning of it. For, going on, it shows in the words that follow what kind of judgment it spoke of; that it is not one of condemnation, but of discrimination. For saith it, "Judge me, O God." What means "Judge me, O God, and discern my cause from an unholy nation"? According to this judgment of discerning, then, "we must all appear before the judgment-seat of Christ." But again, according to the judgment of condemnation, "Whoso believeth in me is passed from death to life," and shall not come into judgment.”

“In the preceding Psalm, David narrated his desire; now he applies prayer to fulfill that desire. And first he sets forth the prayer; second, its effect, at "why are you sorrowful?" Concerning the first he does two things. First he proposes the prayer in general; second, in particular, at "from the unjust man." And first he asks for judgment; second, the effect of the judgment. He asks therefore, "judge me, O God." But this seems to be presumptuous, because he himself says, "enter not into judgment," etc. Ps. 142. I respond. It must be said that there is a twofold judgment: namely, of severity and of mercy or equity. The first is when only the matter is attended to and not the condition of the person; and this is to be feared. Of this he says, Ps. 142: "Enter not into judgment," etc., because our acts of justice are nothing in the sight of God, as is said in Is. 64. And this judgment is without mercy, as is said in Jas. 2. The second is when not only the nature of the matter is considered, but the condition of the person. Ps. 102: "The Lord has had mercy on those who fear Him, for He knows our frame." And this is what he asks for. Or, alternatively, there is a twofold judgment: namely, of examination, when merits are scrutinized -- and this he does not ask for here, because the examination is to be feared. Job 9: "I feared all my works, knowing that you would not spare the offender." The other is of discrimination, namely, separation from the wicked; and this is what he asks for. And so he adds, "and distinguish my cause." And this refers to the present state: and thus we ask to be distinguished from the wicked, if not in place, at least in cause. For many things are common to us and to them, because place is a matter of fortune's lot, but cause is not -- because good and bad use the same circumstances differently, for in adversities the good shine through patience, while the wicked fume with impatience. But if we refer it to the future judgment, we ask to be distinguished, because the cause of the wicked shall be judged unto condemnation, and that of the good unto salvation. In particular, he asks to be judged with regard to two things: namely, with regard to deliverance from evil, and with regard to advancement in good. He asks therefore to be delivered from evil, whether present or future; hence he says, "from the unjust and deceitful man, rescue me." The "unjust man" is a name for the Devil. Mt. 13: "An enemy, a man, has done this." Or any other seducing man, or any unjust person. And he is called unjust because he openly intends injustice; deceitful, on account of hidden fraud. Prov. 12: "Deceit is in the heart of those who plot evil." From these, therefore, one is delivered in two ways. In one way, so as not to be seduced by hidden deceitfulness. In another way, so as not to be crushed by adversity.”