Hadith: Al-‘Abbās ibn ‘Abdul-Muttalib sought permission from the Messenger of Allah (may Allah's peace and blessings be upon him) to spend the nights of Mina in Makkah to provide (the pilgrims with) water, and he permitted him

عن عبد الله بن عُمَر رضي الله عنه قال: «اسْتَأْذَنَ الْعَبَّاسُ بن عَبْدِ الْمُطَّلِب رسول الله صلى الله عليه وسلم : أن يبيت بمكة ليالي مِنى، من أجل سِقَايَتِه فأذن له».
[صحيح] - [متفق عليه]

‘Abdullāh ibn ‘Umar (may Allah be pleased with him) reported: Al-‘Abbās ibn ‘Abdul-Muttalib sought permission from the Messenger of Allah (may Allah's peace and blessings be upon him) to spend the nights of Mina in Makkah to provide (the pilgrims with) water, and he permitted him.
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

Spending the nights of the 11th, 12th and 13th of Dhu al-Hijjah (Tashrīq Nights) at Mina is one of the obligatory acts of Hajj that the Prophet (may Allah's peace and blessings be upon him) observed. Indeed, staying at Mina on those nights and days is an act of obedience to Allah, the Almighty, and from the rites of Hajj. Since providing water for the pilgrims is one of the most favorable acts which draw the slave near to Allah, being a service offered to the pilgrims and guests of His House, the Prophet (may Allah's peace and blessings be upon him) allowed his paternal uncle Al-‘Abbās to leave spending the night in Mina, because he was in charge of providing water for the pilgrims, which was a general benefit. This indicates that other people who are not in charge of similar tasks, and do not have a valid excuse are not entitled to this concession.