The Prophet ﷺ said, "None of you truly believes until he loves for his brother," or "for his neighbor, what he loves for himself." Hajjaj had no doubt about the wording.
حدثنا محمد بن جعفر حدثنا شعبة وحجاج قال حدثني شعبة قال سمعت قتادة يحدث
عن النبي ﷺ أنه قال لا يؤمن أحدكم حتى يحب لأخيه أو لجاره ما يحب لنفسه ولم يشك حجاج
Its isnad is sahih, and it is found in Bukhari 1/10, in the Book of Faith, "It is part of faith that one should love for his brother," and Muslim 1/67 no. 45 with similar wording, and Tirmidhi 4/667 no. 2515, who graded it sahih, and Nasai 8/115 no. 5016.