The two critical words in Gen 1:2 that are used to describe the earth are:
- תֹּהוּ (tohu) = formless
- בֹּהוּ (bohu) = empty
With the earth formless and empty, God proceeds to give form and then fill as follows:
Days 1-3 - Forming or more accurately, Separating
- Day 1 - Light separated from darkness, day separated from night
- Day 2 - Waters above separated from waters below
- Day 3 - Dry land separated from seas/waters
Days 4-6 - Filling and Populating
- Day 4 - lights placed in the firmament of the day and night
- Day 5 - fish placed in the sea and birds in the heavens
- Day 6 - animals placed on the land and man created to work the land.
Thus, the progress of the six days of the creation week follows the simple plan of Gen 1:2, forming and filling the formless and empty.
At the conclusion of each day's activity, God pronounces the work (so far) as "good". However, only when the process is complete at the end of the 6th day does God say that it is "very good".
The implication is that at the beginning of the process earth is "formless and empty" - waiting for the rest of the creation process.
The record of creation in gen has been seen by many as a salvation record: God take an earth that is formless and empty (just like the sinner) and when God is finished the creation process (recreation for a sinner) God pronounces the earth, "very good", just like the saved/redeemed sinner.