| Barnes' Notes on the Bible Thy word have I hid in mine heart - Compare the notes at Psalm 37:31. The word rendered "hid" means properly to conceal, so that a thing may be secret, private, inaccessible; then, to lay up in private, to treasure up. to hoard - as money or jewels - commonly "hidden" from public view. Job 20:26; Psalm 17:14. Then it means to lay up in one's heart, as a secret, inaccessible place; to hide one's thoughts; purposes, designs; or to lay up knowledge or wisdom in the heart as a treasure, Job 10:13; Proverbs 2:1; Proverbs 7:1. The meaning here is, that he had "treasured" up the word of God, as the most valuable thing, in his heart; it was "there," though unseen; it constituted the secret power by which he was governed; it was permanently deposited there, as the most valuable of his treasures. That I might not sin against thee - That it might protect me from sinning against thee. That I might be continually guided by its precepts; that I might be admonished of duty; that I might be deterred from going astray.
Clarke's Commentary on the BibleThy word have I hid in my heart - 7. He must treasure up those portions of God's word in his mind and heart which speak against uncleanness of every kind; and that recommend purity, chastity, and holiness. The word of Christ should dwell richly in him. If God's word be only in his Bible, and not also in his heart, he may soon and easily be surprised into his besetting sin.
Gill's Exposition of the Entire BibleThy word have I hid in mine heart,.... Not only heard and read it, but received it into his affections; mixed it with faith, laid it up in his mind and memory for future use; preserved it in his heart as a choice treasure, where it might dwell richly, and be of service to him on many occasions; and particularly be of the following use: that I might not sin against thee; the word of God is a most powerful antidote against sin, when it has a place in the heart; not only the precepts of it forbid sin, but the promises of it influence and engage to purity of heart and life, and to the perfecting of holiness in the fear of the Lord; and all the doctrines of grace in it effectually teach the saints to deny all sin and worldly lusts, and to live a holy life and conversation; see 2 Corinthians 7:1.
Geneva Study BibleThy word have I {b} hid in mine heart, that I might not sin against thee. (b) If God's word is carved in our hearts, we will be more able to resist the assaults of Satan: and therefore the prophet desires God to instruct him daily more and more in it.
Wesley's Notes 119:11 Hid - I have laid it up in my mind like a choice treasure, to be ready upon all occasions to counsel, quicken or caution me.
Matthew Henry's Concise Commentary119:9-16 To original corruption all have added actual sin. The ruin of the young is either living by no rule at all, or choosing false rules: let them walk by Scripture rules. To doubt of our own wisdom and strength, and to depend upon God, proves the purpose of holiness is sincere. God's word is treasure worth laying up, and there is no laying it up safe but in our hearts, that we may oppose God's precepts to the dominion of sin, his promises to its allurements, and his threatenings to its violence. Let this be our plea with Him to teach us his statutes, that, being partakers of his holiness, we may also partake of his blessedness. And those whose hearts are fed with the bread of life, should with their lips feed many. In the way of God's commandments there is the unsearchable riches of Christ. But we do not meditate on God's precepts to good purpose, unless our good thoughts produce good works. I will not only think of thy statutes, but do them with delight. And it will be well to try the sincerity of our obedience by tracing the spring of it; the reality of our love by cheerfulness in appointed duties.
Matthew Henry's Whole Bible CommentaryVerse 11 Here is, 1. The close application which David made of the word of God to himself: He hid it in his heart, laid it up there, that it might be ready to him whenever he had occasion to use it; he laid it up as that which he valued highly, and had a warm regard for, and which he was afraid of losing and being robbed of. God's word is a treasure worth laying up, and there is no laying it up safely but in our hearts; if we have it only in our houses and hands, enemies may take it from us; if only in our heads, our memories may fail us: but if our hearts be delivered into the mould of it, and the impressions of it remain on our souls, it is safe. 2. The good uses he designed to make of it: That I might not sin against thee. Good men are afraid of sin, and are in care to prevent it; and the most effectual way to prevent is to hide God's word in our hearts, that we may answer every temptation, as our Master did, with, It is written, may oppose God's precepts to the dominion of sin, his promises to its allurements, and his threatenings to its menaces. | 
