Sahih Muslim
The Book of Virtue, Good Manners and Joining of the Ties of Relationship (Kitab Al-Birr was-Salat-I-wal-Adab)
Book Number: 032 / Hadith Number: 6385
'Abdullah reported that a person came to Allah's Messenger (may peace be upon him) and said to Allah's Messenger (may peace be upon him): What is your opinion about the person who loves the people but his (acts or deeds are not identical to theirs)? Thereupon Allah's Messenger (may peace be upon him) said: A person would be along with one whom he loves.