Jamieson, Fausset and Brown on Genesis 1:2

2. the earth was without form and void--or in "confusion and emptiness," as the words are rendered in Is 34:11. This globe, at some undescribed period, having been convulsed and broken up, was a dark and watery waste for ages perhaps, till out of this chaotic state, the present fabric of the world was made to arise.

the Spirit of God moved--literally, continued brooding over it, as a fowl does, when hatching eggs. The immediate agency of the Spirit, by working on the dead and discordant elements, combined, arranged, and ripened them into a state adapted for being the scene of a new creation. The account of this new creation properly begins at the end of this second verse; and the details of the process are described in the natural way an onlooker would have done, who beheld the changes that successively took place.