My tongue shall speak of thy word: for all thy commandments are righteousness.

Jamieson-Fausset-Brown Bible Commentary

172. My tongue shall speak of thy word-literally, "answer Thy Word," that is, with praise, respond to Thy word. Every expression in which we praise God and His Word is a response, or acknowledgment, corresponding to the perfections of Him whom we praise.

Matthew Henry's Concise Commentary

119:169-176 The psalmist desired grace and strength to lift up his prayers, and that the Lord would receive and notice them. He desired to know more of God in Christ; to know more of the doctrines of the word, and the duties of religion. He had a deep sense of unworthiness, and holy fear that his prayer should not come before God; Lord, what I pray for is, what thou hast promised. We have learned nothing to purpose, if we have not learned to praise God. We should always make the word of God the rule of our discourse, so as never to transgress it by sinful speaking, or sinful silence. His own hands are not sufficient, nor can any creature lend him help; therefore he looks up to God, that the hand that had made him may help him. He had made religion his deliberate choice. There is an eternal salvation all the saints long for, and therefore they pray that God would help their way to it. Let thy judgments help me; let all ordinances and all providences, (both are God's judgments,) further me in glorifying God; let them help me for that work. He often looks back with shame and gratitude to his lost estate. He still prays for the tender care of Him who purchased his flock with his own blood, that he may receive from him the gift of eternal life. Seek me, that is, Find me; for God never seeks in vain. Turn me, and I shall be turned. Let this psalm be a touchstone by which to try our hearts, and our lives. Do our hearts, cleansed in Christ's blood, make these prayers, resolutions and confessions our own? Is God's word the standard of our faith, and the law of our practice? Do we use it as pleas with Christ for what we need? Happy those who live in such delightful exercises.

Matthew Henry's Whole Bible Commentary

Verse 172

Observe here, 1. The good knowledge David had of the word of God; he knew it so well that he was ready to own, with the utmost satisfaction, that all God's commandments are not only righteous, but righteousness itself, the rule and standard of righteousness. 2. The good use he resolved to make of that knowledge: My tongue shall speak of thy word, not only utter praise for it to the glory of God, but discourse of it for the instruction and edification of others, as that which he himself was full of (for out of the abundance of the heart the mouth will speak) and as that which he desired others also might be filled with. The more we see of the righteousness of God's commandments the more industrious we should be to bring others acquainted with them, that they may be ruled by them. We should always make the word of God the governor of our discourse, so as never to transgress it by sinful speaking or sinful silence; and we should often make it the subject-matter of our discourse, that it may feed many and minister grace to the hearers.