The Sadducees, who do not believe in the resurrection, asked Jesus a problematic question based on the law of the law of Levirate Marriage given in the book of Deuteronomy. To support their hypothetical question, they said, “Teacher, Moses said, ‘If a man dies without children, his brother shall marry his wife and raise up descendants for his brother’ (Deut 25:5-10).
The law of Levirate Marriage is: “When brothers live together and one of them dies without a son, the widow of the deceased shall not marry anyone outside the family; but her husband’s brother shall come to her, marrying her and performing the duty of a brother-in-law” (Deut 25:5-6). The reason for such a command was to have a son for the deceased brother to continue his name in Israel (Deut 25:7). If the living brother declines to do so, “his sister-in-law, in the presence of the elders, shall go up to him and strip his sandal from his foot and spit in his face, declaring, ‘This is how one should be treated who will not build up his brother’s family!’” (Deut 25:9).
Jesus revealed the nature of life in heaven as an answer to the question of the Sadducees. He said, “At the resurrection they neither marry nor are given in marriage but are like the angels in heaven” (Mt 22:30). According to Hebrew 2:7, God created man “for a little while lower than the angels.” Those who keep the commandments of Jesus will reach heaven and will be like angles from then on. The others will join the devil and his angels in eternal fire (Mt 25:41).