Sahih al-Bukhari 3146
Narrated Anas:
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."
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 ‏"‏‏.‏