Young's Literal Translation
Gen 1:1 In the beginning of God's preparing the heavens and the earth--
Gen 1:2 the earth hath existed waste and void, and darkness is on the face of the deep, and the Spirit of God fluttering on the face of the waters,
YLT
Isa 45:18 For thus said Jehovah, Creator of heaven, He is God, Former of earth, and its Maker, He established it--not empty He prepared it, For inhabiting He formed it: `I am Jehovah, and there is none else.
OK, let's stop focusing on how to translate "tohu wabohu" for a moment. Let's just stick with the 2 words in each verse.
If the YECers are correct, Moses wrote that God created out of nothing the earth and it was "tohu wabohu".
Yet, Isaiah clearly wrote this: God did not create out of nothing the earth "tohu wabohu".
Do you see the glaring contradiction here? Regardless of what English words we might want to insert in each verse, it doesn't matter. It's the Hebrew that counts, and the 2 words occur together in both Gen 1:2 and Isa 45:18.
So, whatever they mean, Moses and Isaiah were referring to creation, by the word "create" (barah).
If there is no time gap, and God did create the earth "tohu wabohu", then he contradicts Isaiah completely, who wrote the exact opposite; that God did not create the earth "tohu wabohu".
The only reasonable conclusion is that v.2 should read "but the earth became "tohu wabohu". Thus, we have a time gap that isn't explained, but just noted by inference of the fact that the earth became something other than what it was at original creation.
In the beginning OF God's PREPARING the earth, it existed empty and the Holy Spirit was moving on the surface of the waters.
This does not, and cannot, explain the contradiction between Moses and Isaiah. If there is no time gap, they are contradicted by each other.
In spite of what Gregg posted about the "gap theorists" doing harm to Scripture, I have just shown that in fact, it is the YECers that are doing great harm to Scripture, by creating a huge contradiction between Moses and Isaiah.