Sahih al-Bukhari 3146
Sahih al-Bukhari · Book 57: One-fifth of Booty to the Cause of Allah (Khumus) · What the Prophet ﷺ used to give to those Muslims whose faith was not so firm, and to other Muslims, from the Khumus or other resources
Narrated Anas:
حَدَّثَنَا أَبُو الْوَلِيدِ ، حَدَّثَنَا شُعْبَةُ ، عَنْ قَتَادَةَ ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم " إِنِّي أُعْطِي قُرَيْشًا أَتَأَلَّفُهُمْ، لأَنَّهُمْ حَدِيثُ عَهْدٍ بِجَاهِلِيَّةٍ " .
The Prophet (ﷺ) said, "I give to Quraish people in order to let them adhere to Islam, for they are near to their life of Ignorance (i.e. they have newly embraced Islam and it is still not strong in their hearts."