The remarkable thing with his deliberations as to the nature of time is that Augustine is reflecting on the subject in conversation with God. The Confessions are his confession to God, a spiritual autobiography in the form of a prayer, and his thoughts on time are no exception. He meditations are punctuated by prayer, "O Lord my God, hear my prayer and let thy mercy attend my longing.", "Let me hear and understand how in the beginning thou madest heaven and earth.", "I am seeking the truth, O Father; I am not affirming it. O my God, direct and rule me." Reasoning corum deo, or before the face of God, Augustine was not afraid to confess his ignorance. Indeed, he has great difficulty in understanding what time is,
He ponders the question that is till raised today, "What was God doing before the creation of the world?"
Augustine was already there in the fifth century. His considered answer to what God was doing before creating the universe was that 'the world was made with time and not in time'. Augustine's God was a being who transcends time, a being located outside time altogether, and responsible for creating time and space as well as matter. Thus Augustine skilfully avoided the problem of why the creation happened at that moment rather than some other, earlier, moment. There were no earlier moments... If the universe originated 'in time', then it cannot have been caused by any physical process that has finite probability, because if it did the the event would already have happened, an infinite time ago. On the other had, if the universe was made 'with time' then this problem goes away. (The Goldilocks Enigma, Paul Davies, Penguin, p. 80-81)
God is an eternal being. From everlasting to everlasting he is God (Psalm 90:2). Time involves an extension of moments, but God is not subject to the passing of time. He simply is. We should not envisage him waiting for ages before implementing his plan to create the universe. Such a time-based category does not apply to a God whose being and knowledge are infinite and eternal. Herman Bavinck comments,
Consequently-strictly speaking-one cannot speak of foreknowledge in the case of God: with him there are no "distinctions of time". He calls the things that are not as if they were and sees what is not as if it already existed. [Citing Augustine] "For what is foreknowledge if not knowledge of future events? But can anything be future to God who surpasses all times? For if God's knowledge includes the very things themselves, they are not future to him, but present; and for this reason we should no longer speak of God's foreknowledge but simply of God's knowledge." [Citing Gregory the Great] "Whatever is past and future to us is immediately present in his sight." (Reformed Dogmatics Volume Two: God and Creation, Herman Bavinck, Baker Academic, p.196-197).
So, to ask "What was God doing before the creation?" is nonsensical. There was no before before the creation, only God in the infinite fullness of his communicative being as Father, Son and Holy Spirit. He is the eternal One and the everlasting Three. He made us and not we ourselves. "In the beginning God created the heavens and the earth" (Genesis 1:1) involved the creation of time as well as space and matter. Our God has placed us in this world of time, Psalm 39:4-5. In Christ God himself entered spacetime when the Son of God became man to redeem us from sin and death (Galatians 4:4-5). He calls us to redeem the time, to use every precious moment of our lives for the glory of his eternal name.