A bound; even the sand of the sea-shore, as it is expressed, Jeremiah 5:22, which, though in itself contemptible, and a very poor defence to the earth against that swelling and raging element, yet by God's almighty power and gracious providence is made sufficient for that purpose; which is noted as a wonderful work of God, Job 38:8, &c. The earth, to wit, the whole earth, as it did in the beginning of the creation. This was God's appointment, and the course of nature settled by him. But when men transgressed their bounds, all the laws of God and men, it is not strange if the waters also transgressed their bounds, and once again overwhelmed the earth in the general deluge.
Related Commentaries of Psalms 104:9
Psalms 104:9
9 Thou hast set a bound that they may not pass over; that they turn not again to cover the earth.