never heard of this before. Where can I read more about this ?
From the Quran, the Jews are reprimanded for being ungrateful, breaking promises, abusing privileges and then killing prophets sent to them. But they are also told that if they fix their ways, Allah (swt) will not torment them anymore. The stories of Jews are used for purpose of imparting lessons to the Believers, just like all the other stories in the Quran. I am not sure there is any such curse that Allah (swt) has inflicted upon them, though I have heard about this since childhood.
The مسخ was a punishment for a group of them:
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The author of Al-Manar said about the wisdom behind their transformation into monkeys and pigs: God Almighty permitted the Children of Israel to work six days a week, and prohibited them from working on one day, which was the Sabbath. He imposed on them on this day the need to strive hard in religious works. To revive the religious feeling in their hearts, and to weaken their greed in accumulating rubbish, and their love of the world, a group of them transgressed the limits of God on the Sabbath and transgressed them. Their punishment for that was the punishment of one who does not satisfy himself with the morals of religion, and the punishment of such a person is to leave the ocean of human perfection and to wander in the pastures of Animalism, like the monkey in its whims, and the pig in its desires. End.
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You are right the prevailing opinion is the Jews as a whole aren't cursed. But also Allah will not accept anything but Islam:
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The Claim That Jews Are Cursed: According to the Holy Quran, the Jews as a people are not cursed, and the cursed ones in the Quran are those Jews who disobeyed God. God is Generous and Forgiving and cannot curse those who did not disobey Him. Every person is responsible for their own good or evil deeds. God Almighty says, “No soul shall bear the burden of another.” As for the verse, “And the Jews say, ‘The hand of God is chained.’ Chained are their hands, and they are cursed for what they say. Rather, His hands are extended; He spends however He wills.” Without a doubt, these are the ones who were cursed. When someone says this, they are denying God and accusing Him of injustice. “God is far above that.” In the case of the verse mentioned above, it refers to a specific example, and it is unwise to read the Quran, or any other holy text, without taking the context into consideration.
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The Jinn DNA ijtihaad:
A fifth statement was narrated on the authority of Mujahid, who said: If a man has intercourse without saying Bismillah, the jinn will surround his urethra and join intercourse with him. This is what God Almighty said: “No man or jinn has touched them before them...” about the Hoor