I disagree, and you skipped verses 24-28. Jesus responded to the specific question the Sadducees had about the widow with the seven husbands. The Sadducees did not ask a question on whether or not there is resurrection here. The gist of Jesus' response was "no marriage after resurrection". When He says there were mistaken, he was referring to the marriage question, not about resurrection.
However, Jesus also discussed resurrection after addressing the marriage issue, but he moved on to a different topic. See below I bolded "But about", "Now about," etc., suggesting transition to a different issue. He moved on to a different topic, since the topic of resurrection is the big issue for the Sadducees and non-believers not a rare example of a woman with seven husbands.
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Matthew 22:23-33 That same day the Sadducees, who say there is no resurrection, came to him with a question. 24 “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. 25 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. 26 The same thing happened to the second and third brother, right on down to the seventh. 27 Finally, the woman died. 28
Now then, at the resurrection, whose wife will she be of the seven, since all of them were married to her?” 29 Jesus replied, “You are in error because you do not know the Scriptures or the power of God. 30 At the resurrection people will neither marry nor be given in marriage; they will be like the angels in heaven. 31
But about the resurrection of the dead—have you not read what God said to you, 32 ‘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.”
Luke 20:27-40 Some of the Sadducees, who say there is no resurrection, came to Jesus with a question. 28 “Teacher,” they said, “Moses wrote for us that if a man’s brother dies and leaves a wife but no children, the man must marry the widow and have children for his brother. 29 Now there were seven brothers. The first one married a woman and died childless. 30 The second 31 and then the third married her, and in the same way the seven died, leaving no children. 32 Finally, the woman died too. 33
Now then, at the resurrection whose wife will she be, since the seven were married to her?” 34 Jesus replied, “The people of this age marry and are given in marriage. 35 But those who are considered worthy of taking part in that age and in the resurrection from the dead will neither marry nor be given in marriage, 36 and they can no longer die; for they are like the angels.
66 They are God’s children, since they are children of the resurrection. 37
But in the account of the bush, even Moses showed that the dead rise, for he calls the Lord ‘the God of Abraham, and the God of Isaac, and the God of Jacob.’ 38 He is not the God of the dead, but of the living, for to him all are alive.” 39 Some of the teachers of the law responded, “Well said, teacher!” 40 And no one dared to ask him any more questions.
Mark 12:18-27 Then the Sadducees, who say there is no resurrection, came to him with a question. 19 “Teacher,” they said, “Moses wrote for us that if a man’s brother dies and leaves a wife but no children, the man must marry the widow and have children for his brother. 20 Now there were seven brothers. The first one married and died without leaving any children. 21 The second one married the widow, but he also died, leaving no child. It was the same with the third. 22 In fact, none of the seven left any children. Last of all, the woman died too. 23
At the resurrection whose wife will she be, since the seven were married to her?” 24 Jesus replied, “Are you not in error because you do not know the Scriptures or the power of God? 25 When the dead rise, they will neither marry nor be given in marriage; they will be like the angels in heaven. 26
Now about the dead rising—have you not read in the book of Moses, in the account of the bush, how God said to him, ‘I am the God of Abraham, the God of Isaac, and the God of Jacob’? 27 He is not the God of the dead, but of the living. You are badly mistaken!”
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