It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Go out on jihad, and you will gain the daughters of al-Asfar (Byzantine women) as spoils." Some of the hypocrites said: "He will put us to trial through women." So Allah, the Mighty and Majestic, revealed this verse: "And among them is he who says: Permit me and do not put me to trial" [al-Tawbah: 49].
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11006