The question begins in Matthew 22:31, "have ye not read that which was spoken unto you by God," and ends here with God's own words, which Mark places "in the bush" (Mark 12:26). The Sadducees had quoted Moses to Jesus (Matthew 22:24), so Jesus answered from Moses too. Barnes says other passages stated the doctrine more clearly (Daniel 12:2; Isaiah 26:19), but "he wished to meet them on their own ground." Gill notes that the Sadducees "expressly denied, that the resurrection could be proved out of the law." Jesus' question pointed them to a verse they knew and asked them to hear what God meant by it.

Jesus answered His own question: "God is not the God of the dead, but of the living" (Matthew 22:32). Mark adds, "ye therefore do greatly err" (Mark 12:27), and Luke, "for all live unto him" (Luke 20:38). "When the multitude heard this, they were astonished at his doctrine" (Matthew 22:33), and the Pharisees heard that He "had put the Sadducees to silence" (Matthew 22:34). Luke records that some scribes said, "Master, thou hast well said" (Luke 20:39).

The quotation comes from Exodus 3:6, where God spoke to Moses "in the bush" (Mark 12:26; Luke 20:37). Barnes points out that by then Abraham, Isaac, and Jacob had been dead for centuries, yet God still spoke of Himself as being their God.

The Sadducees had built their case on Moses (Matthew 22:24). Gill reports that other Jewish teachers held the resurrection to be a fundamental point and labored to prove it "out of the law." Jesus did what the Sadducees thought could not be done, and He did it from a passage about God's covenant with the fathers.

This question reveals what kind of God the Lord is. He binds His name to His people. Matthew Henry writes, "For God to be any one's God supposes some very extraordinary privilege and happiness," more than the patriarchs ever received in their earthly lives. A God who calls Himself their God is a God who keeps them.

The commentators weigh the argument a little differently. Barnes says the passage proves directly that Abraham, Isaac, and Jacob were still alive in their souls, and proves the raising of the body "only by consequence." Gill goes a step further: "God is the God of the whole: and therefore as their souls now live with God, their bodies also will be raised from the dead." Both agree that God's relationship with His people does not end at the grave. The difference matters because it shows how much hope Jesus drew from the short phrase "I am the God."