Hebrews 1:1-3

In the past, God spoke to our forefathers through the prophets at many times and in various ways, but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe. The Son is the radiance of God’s glory and the exact representation of his being, sustaining all things by his powerful word.

God has revealed himself so that everyone knows he exists.