Is Christianity a system of articles of belief? Never. It would be better for a man to hold the most obnoxious untruths, opinions the most irreverent, if at the same time he lived in the faith of the Son of God, that is trusted in God as the Son of God trusted in him, than for him to hold every formula of belief perfectly true, and yet know nothing of a daily life and walk with God. The one, holding doctrines of devils, is yet a child of God. The other, holding doctrines of Christ is of the world — yes, of the devil.
To hold to a doctrine or an opinion with the intellect alone is not to believe it. A man’s real belief is that which he lives by. If a man lives by the love of God, and obedience to God’s law, as far as he has recognized it, then whatever wrong opinions the man holds are outside of him. They are not true, and they cannot really be inside any good man. At the same time, no matter how many correct opinions another man holds, if he does not order his life by the law of God’s love, he is not a child of God. What a man believes is the thing he does, not the thing he thinks.
— George MacDonald, Knowing the Heart of God, p. 20