The ruling on taking priority over water when one is less needy than another.
Chapter on Tayammum
Al-Mughni
Book of Purification
Primary text
If someone who is less in need than another takes precedence over the water and uses it, they have committed a reprehensible act (Musi'), but the action itself is valid (Ajza'ahu). This is because the person with the greater need did not actually own the water; their precedence was based on the severity of their need.