Albert Barnes Commentary Psalms 144:3

"Jehovah, what is man, that thou takest knowledge of him? Or the son of man, that thou makest account of him?" — Psalms 144:3 (ASV)

Lord, what is man, that thou takest knowledge of him? - The sentiment here is the same as in Psalm 8:4, though the language is not precisely the same. See the notes at that passage. The word rendered “that thou takest knowledge of him,” means here to take notice of; to regard. The idea is, it is amazing that a being so insignificant as man should be an object of interest to God, or that One so great should pay any attention to him and to his affairs. In Psalm 8:4, the language is “that thou art mindful of him,” that is, that you do remember him - that you do not altogether pass him over.

In Psalm 8:1-9, the remark is made in view of the heavens as being so exalted in comparison with man. The wonder is that, in view of worlds so vast occupying the divine attention and needing the divine care, “man,” so insignificant, does not pass out of his view altogether. Here, the remark seems to be made in illustration of the idea that there is no strength in man; that he has no power to accomplish anything by himself; that he is entirely dependent on God.

Or the son of man - Man - any of the race. See the notes at Psalm 8:4.

That thou makest account of him! -Psalms 8:4, “that thou visitest him.” See the notes at that passage. The word here means “that you should “think” of him,” that he should ever come into your thought at all.