Hazrat Mus‘ab (ra) bin Umair had the honour of migrating twice; he first migrated to Abyssinia and then also to Medina.
(al-Tabaqaat-ul-Kubra li ibn Sa‘d, Vol. 3, p. 86, Mus‘ab (ra) bin Umair, Dar-ul-Kutub al-Ilmiyyah, Beirut, 1990) (Usdul Ghabah, Vol. 5, p. 175, Mus‘ab (ra) bin Umair, Dar-ul-Kutub al-Ilmiyyah, Beirut, 2003)