What does it mean to believe in God?
To believe in God is to have a living conviction of his existence, his attributes, and his works, and to receive with the whole heart his revealed word concerning the salvation of mankind. The Fathers noted that the Creed does not merely say “I believe that God exists,” but “I believe in (eis) God”, a movement of the whole person toward God. As Blessed Augustine explains: to believe in him is “by believing to love him, by believing to cherish him, by believing to go into him and be incorporated among his members” (Blessed Augustine, Tractates on John, 29.6).
Mere intellectual awareness that God exists is not sufficient, for St James writes: “You believe that God is one! You do well! The demons also believe, and they shudder” (Jas 2:19; see Q484, Q508). Furthermore, it can be said that all human beings would believe in God if they did not suppress this knowledge:
The wrath of God is revealed from heaven against all the ungodliness and unrighteousness of those who suppress the truth in unrighteousness… For since the creation of the world, his invisible things are clearly seen, being perceived through created things, even his everlasting power and divinity… because knowing God, they did not glorify him as God or give him thanks. Instead, they became vain in their reasoning, and their senseless heart was darkened. (Rom 1:18–21)
As the Psalmist says: “The fool has said in his heart, ‘There is no God!’” (Psa 14:1 [13:1 LXX]; 53:1; see Q508). Unbelief, in the biblical view, is not first an intellectual conclusion but a disorder of the heart. Therefore, it is wise and necessary to confess that we believe in God; and this confession is more than intellectual assent, it is an act of faith, offered even amid weakness: “Immediately the father of the child cried out and said, ‘I believe; help my unbelief!’” (Mrk 9:24; see Q003).
