[As] a bounty from Allah and a favor," meaning: by a bounty from Allah and His favor, He did that for them. "And Allah is Knowing" of His creation, "Wise" in His command.
Tafsir of Surat al-Hujurat from verse 9 to verse 10.
﴿فضلا من الله ونعمة﴾ أَي: بِفضل من اللَّه وَنعمته فعل ذَلِك بهم ﴿وَاللَّهُ عَلِيمٌ﴾ بخلقه ﴿حَكِيم﴾ فِي أمره.
تَفْسِير سُورَة الحجرات من الْآيَة ٩ إِلَى آيَة ١٠.