It was narrated from Anas bin Malik that:
"The Messenger of Allah (ﷺ) said: 'None of you truly believes until he loves for his brother" or he said "for his neighbor, what he loves for himself." (IT)
English reference (IT): Vol. 1, Book 1, Hadith 66 (IT)
Arabic reference (IT): Book 1, Hadith 69 (IT)