Hadith: We received a letter from ‘Umar ibn al-Khattāb one year before his death. He said: Cancel every marriage between unmarriageable relatives from among the Magians

عن بجالة قال: كنت كاتبا لِجَزْء بن معاوية، عَمِّ الأحنف، فأتانا كتاب عمر بن الخطاب قبل موته بسنة، فَرِّقُوا بين كل ذِي مَحْرَمٍ من المجوس، ولم يكن عمر أخذ الجِزْيَةَ من المجوس، حتى شهد عبد الرحمن بن عوف أن رسول الله صلى الله عليه وسلم أخذها من مجوس هَجَر.
[صحيح] - [رواه البخاري]

Bajālah reported: I was the clerk of Jaz’ ibn Mu‘āwiyah, Al-Ahnaf’s paternal uncle. We received a letter from ‘Umar ibn al-Khattāb one year before his death. He said: "Cancel every marriage between unmarriageable relatives from among the Magians (Zoroastrians)." ‘Umar did not use to take the Jizyah from the Magians till ‘Abdur-Rahmān ibn ‘Awf testified that the Messenger of Allah (may Allah’s peace and blessings be upon him) had taken Jizyah from the Magians of Hajar.
Sahih/Authentic. - [Al-Bukhari]

Explanation

Bajālah explains that he was a scribe for Jaz’ ibn Mu‘āwiyah, who was appointed by ‘Umar ibn al-Khattāb (may Allah be pleased with him) as the governor of Al-Ahwāz. Jaz’ ibn Mu‘āwiyah was also a paternal uncle of Al-Ahnaf ibn Qays. Bajālah adds that a letter came from ‘Umar ibn al-Khattāb one year before his death ordering every marriage between unmarriageable relatives among the Magians to be cancelled. It means that male Magian subjects who live under Muslims’ rule must be prevented from marrying their unmarriageable female relatives like sisters, mothers, and daughters. That is because this contradicts Islam and they should never be allowed to do it, even if it was permissible in their religion. ‘Umar did not take the Jizyah from the Magians till ‘Abdur-Rahmān ibn ‘Awf testified that the Messenger of Allah (may Allah’s peace and blessings be upon him) had taken Jizyah from the Magians of Hajar, a town in Bahrain.