Musnad Ahmad 788:144

Abu Mu'awiyah narrated to us, from al-A'mash, from Shaqiq, from Abu Musa, who said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, what do you say about a man who loves a people but has not yet joined them?" The Messenger of Allah, may Allah bless him and grant him peace, said: "A person is with those whom he loves." And likewise, Waki' narrated it to us, from Sufyan, from al-A'mash, from Shaqiq, from Abu Musa; and Muhammad ibn 'Ubayd also [narrated it] from Abu Musa.