(248) بَابُ إِذَا أَحَبَّ الرَّجُلُ أَخَاهُ فَلْيُعْلِمْهُ
Anas reported that the Prophet, may Allah bless him and grant himpeace, said, "When two men have love for one another, the better of themis the one who has the strongest love for his companion."
Reference: Al-Adab Al-Mufrad 544
In-book reference: Book 30, Hadith 7
English translation: Book 30, Hadith 544