In Psalm 77, Asaph the Psalmist says, "The sound of Your thunder was in the whirlwind; lightning lit up the world. The earth quakes and shook. Your way went through the sea, and Your path through the great waters, yet Your footprints were unseen."
The power of the invisible God is displayed all around us, and cannot escape our notice; but God has not remained unseen as He has become flesh and has lived and walked among us in the person of Jesus Christ. This is why when Philip said to Christ, "Show us the Father." Jesus replied "If you have seen Me You have seen the Father."
In Christ we have the fullness of God in bodily form. To see Christ was to see God, and to know Christ is to know God.
This is what is behind Christ's statement in John 17:3, "This is eternal life, that they may know You, the only true God, and Jesus Christ whom you have sent." We come to the invisible God through the visible Son, and we come to know God, through that same Son.
May we all come to know Jesus Christ and know Him well, so that we can experience the fullness and abundance of eternal life.