His breath goeth forth - He dies like other people, no matter how exalted he is. See the notes at Isaiah 2:22.
He returneth to his earth - See the notes at Psalms 90:3. The earth - the dust - is “his” -
(a) It is his, as that from which he was made: he turns back to what he was. Genesis 3:19 : “dust thou art, and unto dust shalt thou return.”
(b) The earth - the dust - the grave is his, as it is his home - the place where he will abide.
(c) It is his, as it is the only property which he has in reversion. All that a man - a prince, a nobleman, a monarch, a millionaire - will soon have will be his grave - his few feet of earth. That will be his by right of possession; by the fact that, for the time being, he will occupy it, and not another man. But that, too, may soon become another man’s grave, so that even there he is a tenant only for a time; he has no permanent possession even of a grave. How poor is the richest man!
In that very day - The very day - the moment - that he dies.
His thoughts perish - His purposes; his schemes; his plans; his purposes of conquest and ambition; his schemes for becoming rich or great; his plans of building a house, and laying out his grounds, and enjoying life; his design of making a book, or taking a journey, or giving himself to ease and pleasure. Luke 12:19-20 : “and I will say to my soul, Soul, thou hast much goods laid up for many years; take thine ease, eat, drink, and be merry; but God said unto him, Thou fool! this night thy soul shall be required of time.” Such are all the purposes of men!