After asserting the pre-existence of Wisdom, the writer tells her part in the work of creation. When he prepared the heavens, I was there. When God made the firmament, and divided the waters above it and below (Genesis 1:7), Wisdom cooperated.
When he set a compass upon the face of the depth. חוּג (chug), "circle," or "circuit" (as Job 22:14), means the vault of heaven, conceived of as resting on the ocean which surrounds the earth, in partial accordance with the notion in Homer, who speaks of the streams of ocean flowing back into itself ( ἀψόῤῥοος), 'Iliad,' 18:399; 'Odyssey,' 10:508, etc.
That the reference is not to the marking out a limit for the waters is plain from the consideration that this interpretation would make the verse identical with Proverbs 8:29. Thus in Isaiah 40:22 we have, "It is he that sitteth above the circle (chug) of the earth;" i.
e. the vault of heaven that encircles the earth. Septuagint, "When he marked out ( ἀφώριζε) his throne upon the winds." The translators have referred tchom, "depth," to the waters above.