God is not different to who He has revealed Himself to be in Jesus Christ. Jesus Christ reveals God as God is in His being and action towards human beings.
God does not appear as personal as in Jesus Christ yet is really an abstraction behind the curtain of reality. To see Jesus is to see Father as Father is.
Thus when Paul talks of Christ our life, Paul means that Jesus Christ is indicative of the life that is ours in our trinitarian God.
The distinctiveness and oneness of the trinity is the oneness of love that has reached out to draw you and I into this fellowship of love – of Father, Son and Holy Spirit.
Love is the relationship of the trinity and is the trinity. We have been drawn into this love in the living way of Jesus Christ.
We are one substance with God as sons of God by creation and redemption. Yet we are truly ourselves as we live from our baptism by Christ into the oneness of God. We are baptised into living love.
Thus, “The homoousion* is of primary significance: it stands for the basic insight deriving from God’s self-communication to us, that what God is toward us in his saving economic activity in space and time through Christ and the Holy Spirit, he is antecedently and inherently in himself. The focal point is the Lord Jesus Christ.” (1) We don’t have a personal Jesus and an abstract law-mongering Father God.
Thus God is nothing like the abstraction of the law, nor a compilation and agenda of good versus evil precepts. God is love, life and joy in God’s triune being.
When John says of Jesus, ‘In Him is life and that life is the light of all,’ John is saying that Jesus among us and in us – because He has come in our flesh – is the life, light and of the fullness of God. Jesus Christ is fully God and is one substance with God. In Jesus Christ you are one substance with God. You and Father are one because Christ has come in your flesh.
* Christ is one substance with God
Torrance, Thomas F.. The Christian Doctrine of God, One Being Three Persons (T&T Clark Cornerstones) (p. 99). Bloomsbury Publishing. Kindle Edition.