The word of God carries authority like no other. When God speaks, the matter is settled, and when He speaks, it is in as few words as necessary. God spoke 10 times in Genesis 1 and all of creation is formed in just 282 words. Perhaps what we are told of creation is the abridged edition but God did not need more words to describe His vision nor did He need more time to accomplish His creation. Even if God spoke great volumes man would not be any more inclined to believe that in the beginning God created.