Merits of the Helpers in Madinah (Ansaar) 
Bukhari :: Book 5 :: Volume 58 :: Hadith 261
Narrated Al-Bara:
The first people who came to us (in Medina) were Mus'ab bin 'Umar and Ibn Um Maktum. Then came to us 'Ammar bin Yasir and Bilal.
Merits of the Helpers in Madinah (Ansaar)
Bukhari :: Book 5 :: Volume 58 :: Hadith 261
Narrated Al-Bara:
The first people who came to us (in Medina) were Mus'ab bin 'Umar and Ibn Um Maktum. Then came to us 'Ammar bin Yasir and Bilal.