God’s eternal purpose is to be with us as one of us in Jesus and for us to be with him in Jesus. That is what God has always wanted. For he does not will to be God without us.
But we turned away from God’s design for us. We defied his will for us and in so doing ruined ourselves. But God kept to his purpose pursuing us in love to make us his own in Jesus. He is Immanuel: God with us faithfully fulfilling his purpose for us.
We might say that in Immanuel God happens among us. He is being-in-action, the dynamic reality of the presence of God with us in history. This is who God is. God with us as he really is in this event of Immanuel.
We do not start our thinking about God with general observations and speculations about a static divine being. We always begin with God himself in this unique event – God happening dynamically among in human lowliness to bring us to himself where we belong according to his own purpose
That is why we are to think of God in terms of act and relationship, rather than abstract substance. He cannot be described apart from his actions and ongoing active relations. The only God we may speak about is the God who came among us as one of us – Immanuel. He is the unique act of God himself in human flesh. He alone is God as human acting in the presence and power of the Spirit of God – the event of Immanuel.