Does blowing (نفخ) during prayer invalidate the prayer?
Chapter on the Two Prostrations of Forgetfulness
Al-Mughni
Book of Prayer
Primary text
Blowing during prayer invalidates the prayer if it forms two letters, as this is considered speech (kalam). Ahmad considered blowing equivalent to speech, stating that the prayer is nullified based on the narration from Ibn Abbas, "Whoever blows during prayer has spoken," a view also attributed to Abu Hurairah and Sa'id ibn Jubayr. The position that blowing invalidates the prayer is restricted to instances where two letters are articulated because speech cannot be formed with less than two letters.
Supporting text
A dissenting view holds that blowing does not invalidate the prayer unless two letters are formed. This view is held by some narrations attributed to Ahmad, Ibn Mas'ud, Ibn Abbas, Ibn Sirin, Al-Nakh'i, Yahya ibn Abi Kathir, and Ishaq. Furthermore, the opinion attributed to Abu Hanifa states that if the blowing is heard, it is equivalent to speech, but if not heard, it does not invalidate the prayer.