Matthew 22:31

But as touching the resurrection of the dead, have ye not read that which was spoken unto you by God, saying, I am the God of Abraham, and the God of Isaac, and the God of Jacob? God is not the God of the dead, but of the living. And when the multitudes heard it, they were astonished at his teaching.

Note the contrast. The Sadducees had spoken of what "Moses said," but Christ quoted from the same source and declared the message to have been spoken "by God"! The endorsement of the Bible as God's word is plainly intended. Nor may it be supposed that the "by God" imputation is limited to the conversation of Moses. By the words here and elsewhere, Christ boldly declared the Old Testament to be the word of God, and it should be so received by Christ's disciples forever.

Christ went much further in his effort to correct the ignorance of the Sadducees, and dealt with their fundamental trouble, namely, a failure to believe the Old Testament as God's word. Christ, then, in the presence of the multitude, made an argument for immortality of the soul, basing it absolutely upon what "God said" in Exodus 3:6. The argument is bold, plain, and easily understood. Since God used the present tense in that Old Testament passage, saying, "I AM" instead of "I WAS," etc., it means that Abraham, Isaac, and Jacob are still living. This is a most important case. Christ made an argument on such an important subject as the resurrection to turn upon a single word in the Old Testament, a single verb, and the very tense of the verb at that! What bold confidence in the Scriptures! How strongly Jesus relied upon the Scriptures which the Sadducees despised through their ignorance of them. If the Son of God could afford to put such trust in a single word in the Holy Scriptures, his disciples need not hesitate to trust every word of it without doubt or reservation.

No wonder the multitudes were "astonished" at his teaching. Christ demonstrated that he was no prudent scribe with his proof-texts, no fawning sycophant deferring to the opinions of superiors in the Jewish hierarchy, no mealy-mouth uttering platitudes; but he stood forth plainly in that interview as the Son of God, the Christ of glory, answering with certainty and authority the deepest questions of the human spirit, and doing so with a perfection and grace that confounded the opposition. The Sadducees, like the Pharisees before them, withdrew from the scene, vanquished and shamed in the presence of all.