These four were the first believers and the ones who embraced Islam first.
A blessed group of noble Companions followed them in the early years of the call, may Allah be pleased with them. They included: Abu Ubaidah ibn Al-Jarrah (the trustworthy one of this nation), Said ibn Zayd, Khabab ibn Al-Arat and Abdullah ibn Masoud. Moreover, Jafar ibn Abu Talib and his wife Asma bint Umays, Al-Arqam ibn Abu Al-Arqam, Uthman ibn Mazun, Ammar ibn Yasir and Suhaib ibn Sanan Ar-Rumi embraced Islam. Furthermore, Bilal ibn Rabah, Al-Miqdad, and Yasser and Somaiyah, whose son was Ammar ibn Yasser, were among those who embraced Islam early before others…Ibn Hesham counted them to be more than forty [The Prophet’s Biography by Ibn Hesham].