Takeaways from the three reports:

1 – Zaynab, daughter of the Messenger of Allah ﷺ and his eldest child, was married to Abū al-ʿĀṣ ibn al-Rabīʿ. She embraced Islam and migrated before her husband had either accepted Islam or migrated. When he later embraced Islam and migrated, the Messenger of Allah ﷺ restored her to him.

2 – According to the report of Ibn ʿAbbās (no. 873), the Prophet ﷺ returned his daughter Zaynab to her husband Abū al-ʿĀṣ six years after their separation on the basis of the original marriage, without a new contract. In the narration of ʿAmr ibn Shuʿayb (no. 874), however, the Prophet ﷺ returned Zaynab to Abū al-ʿĀṣ with a fresh marriage contract.

3 – Scholarly assessments of the two narrations:
• Al-Tirmidhī said: “The ḥadīth of Ibn ʿAbbās is sound (ḥasan); there is nothing blameworthy in its chain, and it is stronger than the report of ʿAmr ibn Shuʿayb.”
• Concerning the narration of ʿAmr ibn Shuʿayb, Imām Aḥmad declared it weak and affirmed that the sound report is that of Ibn ʿAbbās. Al-Bukhārī, al-Tirmidhī, al-Bayhaqī, and other ḥadīth masters stated the same.
• Ibn ʿAbd al-Barr remarked: “The report of ʿAmr ibn Shuʿayb is reinforced by general legal principles.”

4 – If both spouses accept Islam together, pronouncing the declaration of faith at the same moment, their marriage remains valid by unanimous agreement, for no religious disparity exists between them. Likewise, if a Muslim man is married to a Jewish or Christian woman and later embraces Islam, their marriage also continues, because it is lawful for a Muslim to initiate marriage with a woman of the People of the Book, and continuance is even more proper.

Scholarly disagreement:
The majority of jurists hold that, if one of two non-scriptural spouses accepts Islam before consummation, the marriage is annulled; and that, if a woman of the People of the Book becomes Muslim while married to a non-scriptural disbeliever,