In the synoptic gospel tradition Matthew, Mark, and Luke all share this story from Jesus’ ministry where the Sadducees challenge Jesus on the Torah and the resurrection (if you do not remember, the Sadducees denied there was such a thing as the resurrection).
Some Sadducees (who say that there is no resurrection) came to Jesus, and began questioning Him, saying, “Teacher, Moses wrote for us that if a man’s brother dies and leaves behind a wife and leaves no child, his brother should marry the wife and raise up children to his brother. There were seven brothers; and the first took a wife, and died leaving no children. The second one married her, and died leaving behind no children; and the third likewise; and so all seven left no children. Last of all the woman died also. In the resurrection, when they rise again, which one’s wife will she be? For all seven had married her.”
Jesus said to them, “Is this not the reason you are mistaken, that you do not understand the Scriptures of the power of God? For when they rise from the dead, they neither marry nor are given in marriage, but are like angels in heaven. But regarding the fact that the dead rise again, have you not read in the book of Moses, in the passage about the burning bush, how God spoke to him, saying, ‘I Am the God of Abraham, and the God of Isaac, and the God of Jacob’? He is not the God of the dead, but of the living; you are greatly mistaken.” (Mark 12:18-27)
Jesus addresses the Sadducees on at least three different levels here.
Marriage
Marriage and procreation are unnecessary functions of the resurrected in the life to come. The purpose of marriage and family is to continue the human race because we face death. God setup a system to keep us from dying out and going extinct. But in the life to come, there is no death and therefore no need to be married and have children. We live forever and do not need to procreate.
Life After Death
Jesus continues with his argument against the Sadducees by showing them their faulty thinking. Reaching back and using as an example a passage of the Torah that they would accept (the Sadducees only accepted the first five books of the Old Testament) Jesus talks about Yahweh revealing himself to Moses in the burning bush. He says that Yahweh is the God of the living not the dead, yet Abraham, Isaac, and Jacob lived centuries before Moses and had been dead and buried long ago. The point here is that though their bodies had died, they were in fact still alive, but not only that, this pointed to the general resurrection that would happen in the future. Because they were still alive in a disembodied state, at some point they would be rejoined to their resurrected bodies.
Exodus and the Kingdom of God
Moses led the people out of bondage and slavery via the Exodus from Egypt. The Jews living at the time of Jesus were also under bondage to the Roman empire. They expected the Messiah to provide some sort of nationalistic/political exodus for them. Jesus, viewing all people being held in bondage to sin, saw the act he was about to undergo (death, burial and resurrection) as a spiritual exodus leading the people out of a bondage of sin and death and into the Kingdom of God.