That same day the Sadducees, who say there is no resurrection, came to him with a question. “Teacher,” they said, “Moses told us that if a man dies without having children, his brother must marry the widow and have children for him. Now there were seven brothers among us. The first one married and died, and since he had no children, he left his wife to his brother. The same thing happened to the second and third brother, right on down to the seventh. Finally, the woman died. Now then, at the resurrection, whose wife will she be of the seven, since all of them were married to her?”
Jesus replied, “You are in error because you do not know the Scriptures or the power of God. At the resurrection people will neither marry nor be given in marriage; they will be like the angels in heaven. But about the resurrection of the dead—have you not read what God said to you, ‘I am the God of Abraham, the God of Isaac, and the God of Jacob’? He is not the God of the dead but of the living.”What's striking is that Jesus uses such a strange passage to support this doctrine -- Exodus 3:6. The reason He does this is that the Sadducees accepted only the first five Books of the Bible, the Torah, also known as the Law of Moses.
When the crowds heard this, they were astonished at his teaching.
We can know this from a number of early Church Fathers. St. Hippolytus of Rome (170-235 A.D.) said that the Sadducees “do not, however, devote attention to prophets, but neither do they to any other sages, except to the law of Moses only, in regard of which, however, they frame no interpretations.”
Origen (184-253) said that “although the Samaritans and Sadducees, who receive the books of Moses alone, would say that there were contained in them predictions regarding Christ, yet certainly not in Jerusalem, which is not even mentioned in the times of Moses, was the prophecy uttered.”
And that interpretation, of course, makes sense. If the Sadducees believed that the rest of the Old Testament was inspired, Jesus could have pointed to verses laying out the Resurrection in explicit terms. Instead, He proves it in a somewhat roundabout way by relying upon Exodus 3:6, which is certainly less than explicit. Doesn’t that strike you as at least a bit odd? And I’m not just reading that into this passage. Jerome (347-420) explicitly tells us that He used this passage because of the Saduccees’ rejection of the rest of the Bible:
“In proof of the resurrection there were many plainer passages which He might have cited; among others that of Isaiah, ‘The dead shall be raised; they that are in the tombs shall rise again’ [Isa 26:29, Septuagint]: and in another place, ‘Many of them that sleep in the dust of the earth shall awake’ [Dan. 12:2].
It is enquired therefore why the Lord should have chosen this testimony which seems ambiguous, and not sufficiently belonging to the truth of the resurrection; and as if by this He had proved the point adds, ‘He is not the God of the dead, but of the living.’
We have said above that the Sadducees confessed neither Angel, nor spirit, nor resurrection of the body, and taught also the death of the soul. But they also received only the five books of Moses, rejecting the Prophets. It would have been foolish therefore to have brought forward testimonies whose authority they did not admit.”So whether you look to Scripture or the Fathers, you can see that the Sadducees used only a Five-Book Canon, the Law of Moses.
“you are in error because you do not know the Scriptures or the power of God,” He's not complaining that they don't have the Book of Daniel, but that they don't read the Book of Exodus, which they do have. Likewise, we Catholics, who have been graced with the full Scriptures, will face a much worse judgment if we ignore them then will Protestants who remained innocently ignorant that there was more of the word of God out there.