In His dealings with certain Sadducees who denied the resurrection of the dead (Matt. 22:23-33; Mk. 12:18-27; Luke 20:37-38), Jesus cited God’s statement to Moses as proof that the dead do rise:
Mar 12:26 And as touching the dead, that they rise: have ye not read in the book of Moses, how in the bush God spake unto him, saying, I am the God of Abraham, and the God of Isaac, and the God of Jacob?
27 He is not the God of the dead, but the God of the living: ye therefore do greatly err.
When God spoke these words to Moses, the patriarchs Abraham, Isaac, and Jacob had been dead for many years, yet God spoke of His being their God:
“God implied that the patriarchs were still alive and that He had a continuing relationship with them as their covenant-keeping God, even though they had died long before. This demonstrates, Jesus concluded, that He is not the God of the dead, in the Sadducean understanding of death as extinction, but of the living. He is still the patriarch’s God which would not be true had they ceased to exist at death, that is, if death ends it all. And His covenant faithfulness implicitly guaranteed their bodily resurrection” (BKC: NT, 163).
Based on Jesus’ use of the OT in His dealings with the Sadducees, it seems that we should also regard three earlier statements as testimony to the resurrection of the dead.
First, in Beersheba, the Lord appeared to Isaac “the same night, and said, ‘I am the God of Abraham thy father: fear not, for I am with thee, and will bless thee, and multiply thy seed for my servant Abraham’s sake’” (Gen. 26:24). Abraham had died some time before this appearance (cf. 25:8), but God spoke of Himself as being Abraham’s God.
Second, in Haran, Jacob had a dream in which he saw a ladder “and, behold, the LORD stood above it, and said, ‘I am the LORD God of Abraham thy father, and the God of Isaac: the land whereon thou liest, to thee will I give it, and to thy seed’” (28:13). Like the earlier reference, this divine utterance testified to the Lord’s being the God of Abraham, who had been dead by this time for some time.
Third, after his father Isaac had died, Jacob came to Beersheba. God appeared to him “in the visions of the night” and said to Jacob, “I am God, the God of thy father: fear not to go down into Egypt; for I will there make of thee a great nation” (46:3).
After God’s repeated testimony to Moses about His being the God of Abraham, Isaac, and Jacob (Ex. 3:6, 15, 16; cf. 3:13), some other divine statements occur that likely should be taken as also at least implicitly communicating the same truth, including the following:
Exo 4:5 That they may believe that the LORD God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared unto thee.
2Ki 20:5 Turn again, and tell Hezekiah the captain of my people, Thus saith the LORD, the God of David thy father, I have heard thy prayer, I have seen thy tears: behold, I will heal thee: on the third day thou shalt go up unto the house of the LORD (cf. Isa. 38:5).
2Ch 21:12 And there came a writing to him from Elijah the prophet, saying, Thus saith the LORD God of David thy father, Because thou hast not walked in the ways of Jehoshaphat thy father, nor in the ways of Asa king of Judah.
In the NT, aside from Jesus’ dealing with the Sadducees, Stephen’s citation of God’s statement to Moses at the burning bush served to proclaim at least implicitly the truth of the resurrection of the dead to his hostile audience (Acts 7:32).
From the biblical data about our God’s being the God of those have been physically dead for many, many years, including Abraham, Isaac, Jacob, and David, we should realize the importance of the doctrine of the resurrection of the dead in Scripture.