The ‘fullness of God’ is a term that can seem overwhelming to me. I am keenly aware of the worship and mystery in considering such things. Worship leads to thanksgiving and mystery leads to faith. There is a single favorite text that helps describe this: ‘The grace of the Lord Jesus Christ, the love of God, and the fellowship of the Holy Spirit, be with you all.’ This Trinitarian salutation expresses the mystery of our faith.
These Three, love, grace and fellowship, express the essential natures and functions of God. The Father is love, Jesus is grace and the Holy Spirit is fellowship. This is the life of God to us. This is the example of spiritual life as compared to natural life. This is the characteristic activity of God and is the substance, principle and definition of such activity.
This essential nature gives the Father his essential function: love.
“For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. For God did not send his Son into the world to condemn the world, but to save the world through him.” Jesus