God is invisible Spirit. We can "see" him working in and through his Christians.
Jhn 4:24 God is a Spirit: and they that worship him must worship him in spirit and in truth.
1Ti 1:17 Now unto the King eternal, immortal, invisible, the only wise God, be honour and glory for ever and ever. Amen.
Jhn 14:23 Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.