| Barnes' Notes on the Bible The righteousness of thy testimonies - The principles of righteousness on which they are founded. Those testimonies - those laws - are not arbitrary, or the mere expressions of will. They are founded on right and justice as seen by God, and his laws are his testimony as to what truth and justice are. Is everlasting - See the notes at Psalm 119:142. Give me understanding, and I shall live - Give me a right view of thy law, and thy truth, and I shall have real life. See the notes at Psalm 119:34.
Clarke's Commentary on the BibleThe righteousness of thy testimonies is everlasting - Thy moral law was not made for one people, or for one particular time; it is as imperishable as thy nature, and of endless obligation. It is that law by which all the children of Adam shall be Judged. Give me understanding - To know and practice it. And I shall live - Shall glorify thee, and live eternally; not for the merit of having done it, but because thou didst fulfill the work of the law in my heart, having saved me from condemnation by it.
Gill's Exposition of the Entire BibleThe righteousness of thy testimonies is everlasting,.... Or, "for ever" (b). The righteousness which they require, or which they publish; the righteousness revealed in the Gospel, which is the righteousness of Christ; See Gill on Psalm 119:142; give me understanding, and I shall live; an understanding of the testimonies of the Lord, of the word of God, the law of God, and Gospel of Christ; an understanding of divine and spiritual things; a clearer and larger understanding of them, which is the gift of God; both that itself at first, and an increase of it here prayed for, the end, issue, and effect of which is life. Such live spiritually, and by faith; they live cheerfully and comfortably, and "for ever", as Aben Ezra and Kimchi repeat from the former clause: for "this is life eternal know the only true God and Jesus Christ"; or to have spiritual understanding of them, and of those things which relate to spiritual peace and comfort here, and eternal happiness hereafter, John 17:3. (b) "in seculum", Pagninus, Montanus, Junius & Tremellius, Piscator, Cocceius; "in aeternum", V. L.
Geneva Study BibleThe righteousness of thy testimonies is everlasting: give me understanding, and I shall {d} live. (d) So that the life of man without the knowledge of God is death.
Matthew Henry's Concise Commentary119:137-144 God never did, and never can do wrong to any. The promises are faithfully performed by Him that made them. Zeal against sin should constrain us to do what we can against it, at least to do more in religion ourselves. Our love to the word of God is evidence of our love to God, because it is designed to make us partake his holiness. Men's real excellency always makes them low in their own eyes. When we are small and despised, we have the more need to remember God's precepts, that we may have them to support us. The law of God is the truth, the standard of holiness, the rule of happiness; but the obedience of Christ alone justifies the believer. Sorrows are often the lot of saints in this vale of tears; they are in heaviness through manifold temptations. There are delights in the word of God, which the saints often most sweetly enjoy when in trouble and anguish. This is life eternal, to know God and Jesus Christ whom he has sent, Joh 17:3. May we live the life of faith and grace here, and be removed to the life of glory hereafter.
Matthew Henry's Whole Bible CommentaryVerses 143-144 These two verses are almost a repetition of the two foregoing verses, but with improvement. 1. David again professes his constant adherence to God and his duty, notwithstanding the many difficulties and discouragements he met with. He had said (v. 14), I am small and despised, and yet adhere to my duty. Here he finds himself not only mean, but miserable, as far as this world could make him so: Trouble and anguish have taken hold on me-trouble without, anguish within; they surprised him, they seized him, they held him. Sorrows are often the lot of saints in this vale of tears; they are in heaviness through manifold temptations. There he had said, Yet do I not forget thy precepts; here he carries his constancy much higher: Yet thy commandments are my delights. All this trouble and anguish did not put his mouth out of taste for the comforts of the word of God, but he could still relish them and find that peace and pleasure in them which all the calamities of this present time could not deprive him of. There are delights, variety of delights, in the word of God, which the saints have often the sweetest enjoyment of when they are in trouble and anguish, 2 Co. 1:5. 2. He again acknowledges the everlasting righteousness of God's word as before (v. 142): The righteousness of thy testimonies is everlasting and cannot be altered; and, when it is admitted in its power into a soul, it is there an abiding principle, a well of living water, Jn. 4:14. We ought to meditate much and often upon the equity and the eternity of the word of God. Here he adds, by way of inference, (1.) His prayer for grace: Give me understanding. Those that know much of the word of God should still covet to know more; for there is more to be known. He does not say, "Give me a further revelation," but, Give me a further understanding; what is revealed we should desire to understand, and what we know to know better; and we must go to God for a heart to know. (2.) His hope of glory: "Give me this renewed understanding, and then I shall live, shall live for ever, shall be eternally happy, and shall be comforted, for the present, in the prospect of it." This is life eternal, to know God, Jn. 17:3. 19. KOPH. | 
