How do we know the doctrine of God's existence is true?

The truth of God's existence can be observed through the created world and the inherent moral consciousness in humanity. Romans 1 teaches that what can be known about God is plain to them because God has shown it to them, making divine attributes evident in creation. Furthermore, the conscience serves as an internal witness of God's moral law, revealing to all people a sense of right and wrong, amounting to a witness of His existence and sovereignty. This is further emphasized in Psalm 53, where the foolishness of denying God comes from a refusal to acknowledge the clear evidences of His creation.