Flopfoot:
CCC 156 What moves us to believe is not the fact that revealed truths appear as true and intelligible in the light of our natural reason: we believe “because of the authority of God himself who reveals them, who can neither deceive nor be deceived”.
But I thought that God can do anything and everything. Is God really incapable of deceiving?
God can be spoken of as deceiving, as in 1 Kings 22 - but God cannot deceive. Descriptions of God are not God Himself - which is why the supreme revelation of God is not a book, not even a most holy book, but a Person. The Bible is a marvellous gift of God, and those who know it best are the very people who never cease finding new depths of meaning in it; but it is not as full a revelation of God as Jesus Christ.
Human words are not human persons, so they don’t altogether reveal them - only one Divine Word is a Divine Person. So human words and human acts are too small to fully convey the Presence of God.
God’s faithful undeceiving Love is most of all shown by His acts, for mere words don’t go far enough; and the Passion is the greatest of those acts; everything else follows from it. The Father did not save us by revealing assertions about the Divine Nature - He gaves what is better; He saves us in and through the Son Whom He Loves, & Who Loves Him. He did not only speak - He acted, so that He backed up what He said, by deeds. Words are cheap - so He showed the full extent of His Love. Talk is easy - but only an Incarnate God can die and triumph over death by dying. That is how faithful God is, and how incapable of deceit.
We deceive - but we are sinners, not the God Who insists time & again on His Faithfulness. To say He can deceive, is to see Him through the distorting medium of our own wretchedness & poverty; it’s to “project” our limitations on the God Whose Goodness is unlimited - to make Him less than God, to “un-God” Him. If He is God at all, He cannot be less than utterly deceitless.
And just in case we hadn’t got the lesson (He spends a lot of time in the gospels complaining of the slowness and hard-heartedness of his hearers), He gave us the sacraments, in which the reality of His acts is renewed, in all their saving power. Every Mass is a reminder that He is still faithful. Every instant we live is a proof that that He maintains us in being by His Love. To say “I believe in God, Creator of Heaven and Earth”, is implicitly to say that He is faithful; because without Him, nothing at all could endure for even an instant. ##