[NHEB Luke 20:27-40]
27Some of the Sadducees came to him, those who deny that there is a resurrection. 28They asked him, "Teacher, Moses wrote to us that if a man's brother dies having a wife, and he is childless, his brother should take the wife, and raise up children for his brother. 29There were therefore seven brothers. The first took a wife, and died childless. 30The second and 31the third took her, and likewise the seven all left no children, and died. 32Afterward the woman also died. 33Therefore in the resurrection whose wife of them will she be? For the seven had her as a wife." 34Jesus said to them, "The people of this age marry and are given to someone to marry. 35But those who are regarded as worthy of a place in that age and the resurrection from the dead neither marry nor are given to someone to marry. 36For they cannot die any more, for they are like the angels, and are children of God, being children of the resurrection. 37But that the dead are raised, even Moses showed at the bush, when he called the Lord 'The God of Abraham, and the God of Isaac, and the God of Jacob.' 38Now he is not the God of the dead, but of the living, for all are alive to him." 39Some of the scribes answered, "Teacher, you speak well." 40They did not dare to ask him any more questions.
No resurrection - The word "resurrection" usually means the raising up the "body" to life after it is dead, John 11:24; John 5:29; 1 Corinthians 15:22. But the Sadducees not only denied this, but also a future state, and the separate existence of the soul after death altogether, as well as the existence of angels and spirits, Acts 23:8. Both these doctrines have commonly stood or fallen together, and the answer of our Saviour respects both, though it more distinctly refers "to the separate existence of the soul, and to a future state of rewards and punishments," than to the resurrection of the body. (Barnes Notes on the Bible)
The Sadducees rejected the afterlife (just as the reformed Christians reject the commandments); the answer of Jesus demonstrated that the believers are alive with God, despite their deaths. They are merely physically dead. They believed, the physical life is all there is, and there is no afterlife, no hope. It is an idiomatic saying that God doesn't represent death, but life. He is the resurrection, which is the opposite of permanent death or cessation of the soul. The sense is not the physical death, which is certain for everyone. Pay attention to the figurative language. All the dead will be resurrected to receive judgment, whether unto life, or unto judgment/death.
In case we are tempted to believe that the dead now reside in heaven, Jesus was clear:
John 3:13: "No one has ascended into heaven
no man hath ascended, &c.—There is something paradoxical in this language—"No one has gone up but He that came down, even He who is at once both up and down." Doubtless it was intended to startle and constrain His auditor to think that there must be mysterious elements in His Person. The old Socinians, to subvert the doctrine of the pre-existence of Christ, seized upon this passage as teaching that the man Jesus was secretly caught up to heaven to receive His instructions, and then "came down from heaven" to deliver them. But the sense manifestly is this: "The perfect knowledge of God is not obtained by any man's going up from earth to heaven to receive it—no man hath so ascended—but He whose proper habitation, in His essential and eternal nature, is heaven, hath, by taking human flesh, descended as the Son of man to disclose the Father, whom He knows by immediate gaze alike in the flesh as before He assumed it, being essentially and unchangeably 'in the bosom of the Father'" (Joh 1:18).
Nicodemus was surprised and perplexed, he could not believe the words of Jesus to be plausible. The phrase means, nobody has/can ascend into heaven (something seemingly impossible or the hardest thing to do), Jesus alone who descended from heaven has made it possible by revealing everything, the seemingly impossible wisdom in so simple words. It is a figure of speech. Maybe Nicodemus thought it is too hard for man to be born from above. How can we live righteously and obey God? It is impossible; as the so-called Christians believe, like the rich young man.
[NHEB Deut 30:11-14]
11For this commandment which I command you this day is not too difficult for you, nor is it far off. 12It is not in heaven, that you should say, "Who will go up into heaven for us, and get it for us, and proclaim it to us, that we may obey it?" 13And it is not in the deep of the sea, that you should say, "Who will go down into the deep of the sea for us, and get it for us, and proclaim it to us, so that we may obey it?" 14But the word is very near to you; it is in your mouth and in your heart and in your hand, so that you can do it.
- Matt 8:21 Then another of His disciples said to Him, “Lord, let me
first go and bury my father.” 22 But Jesus said to him, “Follow Me,
and let the dead bury their own dead.”
Living people are figuratively called "dead", to do the dead works and rituals like funeral or burial (comparatively to works discipleship of God). The dead are indeed alive to God, who belong to God that they are not even called dead but asleep: Vine's dictionary.
He is "the firstfruits of them that have fallen asleep," 1Cr 15:20; of saints who departed before Christ came, Mat 27:52; Act 13:36; of Lazarus, while Christ was yet upon the earth, Jhn 11:11; of believers since the Ascension, 1Th 4:13-15; Act 7:60; >1Cr 7:39; 11:30; 15:6, 18, 51; 2Pe 3:4.
Note: "This metaphorical use of the word sleep is appropriate, because of the similarity in appearance between a sleeping body and a dead body; restfulness and peace normally characterize both. The object of the metaphor is to suggest that, as the sleeper does not cease to exist while his body sleeps, so the dead person continues to exist despite his absence from the region in which those who remain can communicate with him, and that, as sleep is known to be temporary, so the death of the body will be found to be....