From Sahih Bukhari (Hadith 1634):
Narrated Ibn `Umar:Al `Abbas bin `Abdul-Muttalib asked the permission of Allah's Messenger (ﷺ) to let him stay in Mecca during the nights of Mina in order to provide the pilgrims with water to drink, so the Prophet (ﷺ) permitted him
Reference: Bukhari 1634