He (God) did not leave himself without witness, in that he did good, gave us rain from heaven and fruitful seasons. Acts 14:17
No-one can see God. Does that mean that God does not exist? That would be a foolish conclusion. Even if we cannot see Him, he has revealed His existence in manifold ways:
By creation. A master craftsman is recognized by his work. “What may be known of God is manifest…for since the creation of the world his invisible attributes are clearly seen, being understood by the things that are made, even his eternal power and Godhead, so that they are without excuse” (Romans 1:19,20).
Through our conscience and personal experiences. God has given each person a conscience as a pointer to good and evil (Romans 2:15). And he permits us to experience his goodness frequently in the circumstances of our lives. (Matthew 5:45, Acts 17:25.)
By the fulfillment of prophecy. God who alone knows the future, has given numerous prophecies in the Bible that have been fulfilled. “Remember…… I am God, and there is none other declaring the end from the beginning” (Isaiah 46: 9,10)
Through Jesus Christ, His Son. In Jesus of Nazareth, God has revealed himself fully. “No one has seen God at any time. The only begotten Son, who is in the bosom of the Father, he has declared him”. (John 1:18) God has revealed himself. Whoever wishes to, can experience Him, His presence and His love