The Lord knoweth the thoughts of man - That is, He who teaches people all that they know Psalm 94:10, must understand all that there is in the mind. See the notes at 1 Corinthians 3:20.

That they are vanity - That is, that they are foolish, vain, unwise, wicked. The knowledge of the thoughts themselves carries with it also the knowledge that they are vain and foolish - for that is their character, and to know them truly is to know this of them. They do not appear to him as they do to people themselves. They are to his view stripped of all that is flattering and illusive, and are seen to be vain and foolish.

The Lord knoweth the thoughts of man,.... He not only hears their words, and sees their actions; but he knows their thoughts, the secret thoughts of their hearts, though he is afar off from them, and, they from him; he is the searcher of the hearts and trier of the reins of the children of men; see Psalm 139:2, and so is Christ, who is the omniscient God, and is the Jehovah all along spoken to and of in this psalm; he knows the thoughts of men, and is a critical discerner of them, Matthew 9:3.

that they are vanity; either that their thoughts are vanity; the object of them is vanity, the riches and honours of this world, which are all vanity and vexation of spirit; and sinful lusts and pleasures, which are vain and useless, yea, pernicious and hurtful: and so they are in their issue and event; they come to nothing, they are without effect; the Lord disappoints men's devices, and frustrates their designs; they think of this and the other, form schemes, but cannot execute them: or else the sense is, that they themselves are vanity, as man in his best estate is; even every man, whether of high or low degree; see Psalm 39:5. The Syriac version is, "for they are a vapour"; with which compare James 4:14. Thales, an Heathen philosopher (e), being asked whether men's deeds could be hid from God, answered, no, nor their thoughts.

(e) Apud Laert. Vit. ejus, Valer. Maxim. l. 7. c. 2. extern. 8.

The LORD knoweth the thoughts of man, that they are vanity.

94:11 Thoughts - Yes, he knoweth all things, even the most secret things, as the thoughts of men; and in particular your thoughts; much more your practices.

94:1-11 We may with boldness appeal to God; for he is the almighty Judge by whom every man is judged. Let this encourage those who suffer wrong, to bear it with silence, committing themselves to Him who judges righteously. These prayers are prophecies, which speak terror to the sons of violence. There will come a day of reckoning for all the hard speeches which ungodly sinners have spoken against God, his truths, and ways, and people. It would hardly be believed, if we did not witness it, that millions of rational creatures should live, move, speak, hear, understand, and do what they purpose, yet act as if they believed that God would not punish the abuse of his gifts. As all knowledge is from God, no doubt he knows all the thoughts of the children of men, and knows that the imaginations of the thoughts of men's hearts are only evil, and that continually. Even in good thoughts there is a want of being fixed, which may be called vanity. It concerns us to keep a strict watch over our thoughts, because God takes particular notice of them. Thoughts are words to God.