[1] Born in Islamic Spain, Ibn Qasim moved to Iraq for a time, and studied under Dawud al-Zahiri.
He left the Malikite school of Muslim jurisprudence for the Zahirite branch, and was considered by Christopher Melchert to be the first Zahirite in the region.
[2] Ibn Qasim copied his teacher's books by hand and was responsible for spreading them throughout Al-Andalus.
[3] He was listed by later Zahirite jurist Ibn Hazm as having been, along with Ruwaym, Ibn al-Mughallis and Mundhir bin Sa'īd al-Ballūṭī, one of the primary proponents of the Zahirite school of Islamic law.
[3] Ibn Hazm, who was also an early champion of the school, was essentially reviving Ibn Qasim's efforts;[4] earlier Zahirites such as Balluti kept their views to themselves.