Tafsir Ibn Kathir (abridged)
The Believers of the People of the Scriptures will earn Double their Rewards
Earlier we mentioned a Hadith that An-Nasa'i collected from Ibn `Abbas that this Ayah is about the People of the Scriptures who believe in Islam, and that they will earn double their reward if they do so. There is an Ayah in Surat Al-Qasas to support this meaning. Also, there is a Hadith from Ash-Sha`bi from Abu Burdah from his father from Abu Musa Al-Ash`ari that the Messenger of Allah ﷺ said,
«ثَلَاثَةٌ يُؤْتَوْنَ أَجْرَهُمْ مَرَّتَيْنِ: رَجُلٌ مِنْ أَهْلِ الْكِتَابِ آمَنَ بِنَبِيِّهِ وَآمَنَ بِي فَلَهُ أَجْرَانِ، وَعَبْدٌ مَمْلُوكٌ أَدَّى حَقَّ اللهِ وَحَقَّ مَوَالِيهِ فَلَهُ أَجْرَانِ، وَرَجُلٌ أَدَّبَ أَمَتَهُ فَأَحْسَنَ تَأْدِيبَهَا، ثُمَّ أَعْتَقَهَا وَتَزَوَّجَهَا فَلَهُ أَجْرَان»
Continue reading the tafsir of ayahs 28–29