15 “I have well declared Your righteousness in the great congregation”. He now addresses His members. He is exhorting them to do what He has already done. He has “declared;” let us declare also. He has suffered; let us “suffer with Him.” He has been glorified; we shall be “glorified with Him.” “I have declared Your righteousness in the great congregation.” How great an one is that? In all the world. How great is it? Even among all nations. Why among all nations? Because He is “the Seed of Abraham, in whom all nations shall be blessed.” Why among all nations? “Because their sound has gone forth into all lands.” “Lo! I will not refrain my lips, O Lord, and that You know.” My lips speak; I will not “refrain” them from speaking. My lips indeed sound audibly in the ears of men; but “You know” mine heart. “I will not refrain my lips, O Lord; that You know.” It is one thing that man hears; another that God “knows.” That the “declaring” of it should not be confined to the lips alone, and that it might not be said of us, “Whatsoever things they say unto you, do; but do not after their works;” or lest it should be said to the people, “praising God with their lips, but not with their heart,” “This people honours Me with their lips, but their heart is far from Me;” do thou make audible confession with your lips; draw near with your heart also. “For with the heart man believes unto righteousness; but with the mouth confession is made unto salvation.” In case like which that thief was found, who, hanging on the Cross with the Lord, did on the Cross acknowledge the Lord. Others had refused to acknowledge Him while working miracles; this man acknowledged Him when hanging on the Cross. That thief had every other member pierced through; his hands were fastened by the nails; his feet were pierced also; his whole body was fastened to the tree; the body was not disengaged in its other members; the heart and the tongue were disengaged; “with the heart” he “believed; with the tongue” he made “confession.” “Remember me, O Lord,” he said, “when You come into Your kingdom.” He hoped for the coming of his salvation at a time far remote; he was content to receive it after a long delay; his hope rested on an object far remote. The day, however, was not postponed! The answer was, “This day shall you be with Me in Paradise.” Paradise has happy trees! This day have you been with Me on “the Tree” of the Cross. This day shall you be with Me on “the Tree” of Salvation....
16. “I have not hid my righteousness within my heart”. What is meant by “my righteousness”? My faith. For, “the just shall live by faith.” As suppose the persecutor under threat of punishment, as they were once allowed to do, puts you to the question, “What are you? Pagan or Christian?” “A Christian.” That is his “righteousness.” He believes; he “lives by faith.” He does not “hide his righteousness within his heart.” He has not said in his heart, “I do indeed believe in Christ; but I will not tell what I believe to this persecutor, who is raging against me, and threatening me. My God knows that inwardly, within my heart, I do believe. He knows that I renounce Him not.” Lo! You say that you have this inwardly within your heart! What have you upon your lips? “I am not a Christian.” Your lips bear witness against your heart. “I have not hid my righteousness within my heart.”...
17. “I have declared Your Truth and Your Salvation.” I have declared Your Christ. This is the meaning of, “I have declared Your Truth and Your Salvation.” How is “Your Truth” Christ? “I am the Truth.” How is Christ “His Salvation”? Simeon recognised the infant in His Mother's hands in the Temple, and said, “For my eyes have seen Your Salvation.” The old man recognised the little child; the old man having himself “become a little child” in that infant, having been renewed by faith. For he had received an oracle from God; and it said this, The Lord had said unto him, that he was not to depart out of this life, until he had seen the “Salvation of God.” This “Salvation of God” it is a good thing to have shown unto men; but let them cry, “Show us Your mercy, O Lord, and grant us Your Salvation.”...
18. “I have not concealed Your mercy and Your Truth from the great congregation.” Let us be there; let us also be numbered among the members of this Body: let us not keep back “the mercy” of the Lord, and “the Truth” of the Lord. Would you hear what “the mercy of the Lord” is? Depart from your sins; He will forgive your sins. Would you hear what “the truth” of the Lord is? Hold fast righteousness. Your righteousness shall receive a crown. For mercy is announced to you now; “Truth” is to be shown unto you hereafter. For God is not merciful in such a way as not to be just, nor just in such a way as not to be merciful. Does that mercy seem to you an inconsiderable one? He will not impute unto you all your former sins: you have lived ill up to this present day; you are still living; this day live well; then you will not “conceal” this “mercy.” If this is meant by “mercy,” what is meant by “truth”?...
19. “Remove not Thou Your mercies far from me, O Lord”. He is turning his attention to the wounded members. Because I have not “concealed Your mercy and Your Truth from the great congregation,” from the Unity of the Universal Church, look Thou on Your afflicted members, look on those who are guilty of sins of omission, and on those who are guilty of sins of commission: and withhold not Thou Your mercies. “Your mercy and Your Truth have continually preserved me.” I should not dare to turn from my evil way, were I not assured of remission; I could not endure so as to persevere, if I were not assured of the fulfilment of Your promise....
“Innumerable evils have compassed me about”. Who can number sins? Who can count his own sins, and those of others? A burden under which he was groaning, who said, “Cleanse Thou me from my secret faults; and from the faults of others, spare Thou Your servant, O Lord.” Our own are too little; those “of others” are added to the burden. I fear for myself; I fear for a virtuous brother, I have to bear with a wicked brother; and under such burden what shall we be, if God's mercy were to fail? “But You, Lord, remove not afar off.” Be Thou near unto us! To whom is the Lord near? “Even” unto them that “are of a broken heart.” He is far from the proud: He is near to the humble. “For though the Lord is high, yet has He respect unto the lowly.” But let not those that are proud think themselves to be unobserved: for the things that are high, He “beholds afar off.” He “beheld afar off” the Pharisee, who boasted himself; He was near at hand to succour the Publican, who made confession. The one extolled his own merits, and concealed his wounds; the other boasted not of his merits, but laid bare his wounds. He came to the Physician; he knew that he was sick, and that he required to be made whole; he “dared not lift up his eyes to Heaven: he smote upon his breast.” He spared not himself, that God might spare him; he acknowledged himself guilty, that God might “ignore” the charge against him. He punished himself, that God might free him from punishment....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)