These verses are explained in the notes on Matthew 22:23-33. He is not the God of the dead, but of the living That is, (if the argument be proposed at length,) since the character of his being the God of any persons, plainly intimates a relation to them, not as dead, but as living; and since he cannot be said to be at present their God at all, if they are utterly dead; nor to be the God of human persons, such as Abraham, Isaac, and Jacob, consisting of souls and bodies, if their bodies were to abide in everlasting death; there must needs be a future state of blessedness, and a resurrection of the body, to share with the soul in it.
Related Commentaries of Mark 12:18
Mark 12:18-20
18 Then come unto him the Sadducees, which say there is no resurrection; and they asked him, saying,
19 Master, Moses wrote unto us, If a man's brother die, and leave his wife behind him, and leave no children, that his brother should take his wife, and raise up seed unto his brother.
20 Now there were seven brethren: and the first took a wife, and dying left no seed.