The Messenger of Allah ﷺ said, "There is no alliance in Islam, but any alliance made during the days of ignorance is only strengthened by Islam."
قال حدثنا عبد الله بن محمد حدثنا ابن نمير وأبو أسامة عن زكريا عن سعد بن إبراهيم عن أبيه
قال رسول الله ﷺ لا حلف في الإسلام وأيما حلف كان في الجاهلية لم يزده الإسلام إلا شدة
Its isnad is sahih. Ibn Numayr is Abdullah, and Abu Usama is Hammad bin Usama Qurashi, their client, the trustworthy and firmly reliable narrator. Saad bin Ibrahim bin Abdul-Rahman bin Awf is trustworthy, firmly reliable, and excellent, as is his father, and his father had seen the Prophet. The hadith has already appeared as number 13921, where we commented on it.