The Sadducees had used Moses to make the resurrection look foolish (Mark 12:19-23). Jesus first told them they knew "not the scriptures, neither the power of God" (Mark 12:24). Now He shows them the Scripture they had missed, and He takes it from the same book of Moses they had quoted. His question presses them to admit that they had read these words without seeing what they meant. Matthew Henry draws out the point of the present tense: "I am the God of Abraham; not only, I was so, but I am so." Gill reasons that since God is still their God, "they must be now alive in their souls," and their bodies must rise, or He would not be "the God of their whole persons."

Jesus answers His own question in the next breath: "He is not the God of the dead, but the God of the living: ye therefore do greatly err" (Mark 12:27). Mark records no reply from the Sadducees. The next thing Mark tells us is that a scribe who had heard the debate perceived "that he had answered them well" (Mark 12:28). Luke adds that certain scribes said, "Master, thou hast well said," and that after that "they durst not ask him any question at all" (Luke 20:39-40).

The Sadducees accepted the law of Moses, and their question rested on the law that a man should marry his dead brother's widow and "raise up seed unto his brother" (Mark 12:19). So Jesus answers from Moses too. "The bush" means the burning bush, where God spoke to Moses and said, "I am the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob" (Exodus 3:6). Barnes explains that before the Bible was divided into chapters and verses, the easiest way to cite a passage was "by the subject," so "in the bush" means in the part of Exodus that tells about the burning bush. When God spoke these words to Moses, Abraham, Isaac, and Jacob had been dead for generations.

This question shows that God's covenant does not end at the grave. God did not say to Moses, "I was the God of Abraham," but "I am" (Exodus 3:6). A God who binds His name to people does not lose them to death. Luke records Jesus adding, "for all live unto him" (Luke 20:38).

The Sadducees thought the resurrection was a puzzle that made Scripture look foolish. Jesus showed that the real problem was a small view of God. They had the right book but did not know "the power of God" (Mark 12:24). The hope of resurrection rests not on clever answers about the next life but on who God is and on His faithfulness to those who are His.