There came to him some Sadducees, those who deny that there is a resurrection, and they asked him a question, saying, “Teacher, Moses wrote for us that if a man’s brother dies, having a wife but no children, the man must take the widow and raise up offspring for his brother. Now there were seven brothers. The first took a wife, and died without children. And the second and the third took her, and likewise all seven left no children and died. Afterward the woman also died. In the resurrection, therefore, whose wife will the woman be? For the seven had her as wife.”
And Jesus said to them, “The sons of this age marry and are given in marriage, but those who are considered worthy to attain to that age and to the resurrection from the dead neither marry nor are given in marriage, for they cannot die anymore, because they are equal to angels and are sons of God, being sons of the resurrection. But that the dead are raised, even Moses showed, in the passage about the bush, where he calls the Lord the God of Abraham and the God of Isaac and the God of Jacob. Now he is not God of the dead, but of the living, for all live to him.” Then some of the scribes answered, “Teacher, you have spoken well.” For they no longer dared to ask him any question. Luke 20:27-40.
I love this because it is one of the places where Jesus taught us there is a life after this one. And it operates under different rules than this one. And it is already the reality of believers who have passed from this life, like Abraham, Isaac, Jacob, and any of your recently deceased friends and relatives who died in Christ.
The spiritual realm is separated from this realm for a reason. This realm, on the earth, was given to man. Through disobedience this world came under the curse that we all experience today: thorns, weeds, disease, and estrangement from the animal kingdom (Genesis 9:2). After all, sin did not enter the world through them, but they suffer for it because man was given dominion over them. That will be different when this realm is finally done away with, and then the wolf will graze with the lamb, and the child will lead them (Isaiah 11:6).
One day this world will pass away, along with its sin and suffering. There will still be a separation in the spiritual realm for those who refuse the rule of God. But those who submit themselves to God’s rule, who have their sin taken away through faith in Christ, our savior, will live in a world where there is no curse or suffering. Those of us who were married, who were “one flesh,” shall leave the flesh behind to become one in Christ, co-heirs of eternal life.