No God made the universe, the 'heavens and the earth', in an instant. The creation of life in general and man in particular happened over the space of 6 days but the actual creation didn't take all day. The phrase, 'heaven and the earth', is a Hebrew expression meaning the universe. All we really get from this passage is that the cosmos and earth were created, 'in the beginning'. The perspective of creation week is from the surface of the earth, starting with the Spirit of God hovering over the deep (Gen. 1:2). In the chapter there are three words used for God's work in creation. The first is 'created' ('bara' H1254) a very precise term used only of God.
Create ‘bara’ (H1254) - 'This verb has profound theological significance, since it has only God as it’s subject. Only God can create in the sense implied by bara. The verb expresses the idea of creation out of nothing...(Vines Expository Dictionary)
It is used once to describe the creation of the universe (Gen 1:1), then again to describe the creation of life (Gen 1:21). Finally, in the closing verses, it is used three times for the creation of Adam and Eve (Gen. 1:27).
The doctrine of creation isn't just an historical narrative that can be taken literally or figuratively, it's a New Testament doctrine inextricably linked to original sin. The Scriptures offer an explanation for man's fallen nature, how we inherited it exactly is not important but when Adam and Eve sinned we did not fast. This is affirmed in the New Testament in no uncertain terms by Luke in his genealogy, in Paul's exposition of the Gospel in Romans and even Jesus called the marriage of Adam and Eve 'the beginning'.
Grace and peace,
Mark