Is rinsing the nose (Istinshaq) obligatory in purification?
Chapter on the Obligation of Purification
Al-Mughni
Book of Purification
Primary text
Rinsing the nose is obligatory in both forms of purification according to one narration by Al-Qadi, supported by Abu Ubaid, Abu Thawr, and Ibn al-Mundhir. The evidence is the Prophet's command: "Whoever performs Wudu, let him seek expulsion of water from his nose" and "When one of you performs Wudu, let him put water in his nose and then expel it," which is agreed upon (Muttafaq 'alayh). Another narration states: "Whoever performs Wudu, let him rinse his nose." Ibn Abbas narrated that the Prophet commanded: "Expel the water from the nose two or three times with force." This command necessitates obligation because the nose remains open and uncovered, unlike the mouth.
Supporting text
Another narration from Ahmad, cited by scholars other than Al-Qadi, suggests that gargling (Mamdah) and rinsing the nose are obligatory in the major purification (Ghusl) but merely recommended (Sunnah) in the minor purification (Wudu). This is the view of Al-Thawri and the Ahl al-Ra'y, based on the reason that Ghusl requires washing everything possible, including dense hair roots, whereas Wudu does not.