Shaykh Maulana Usman Muneeb
Benefits and Issues:
➊ The detail of this supplication is as follows: A Bedouin came and began to pray with the Messenger of Allah (sallallahu alayhi wa sallam), and he supplicated, "O Allah, have mercy on me and on Muhammad (sallallahu alayhi wa sallam), and do not have mercy on anyone else along with us." The Prophet (sallallahu alayhi wa sallam) admonished him and said, "You have limited the vast mercy of Allah, the Exalted." (Sahih al-Bukhari, al-Adab, Hadith: 6010)
The meaning was that how could His mercy be diminished if He were to show mercy to others as well? In an authentic narration, it is mentioned that Allah, the Exalted, has divided mercy into one hundred parts; He has given one part to the creation in this world, by which the servants and animals show mercy to one another, and ninety-nine parts remain with Him. So, what perfection must His mercy possess!
➋ From this, it is understood that one should not be miserly in supplication; rather, one should supplicate for goodness for one's friends, companions, and every Muslim along with oneself. For every good that is asked for others, Allah, the Exalted, grants it to the supplicant as well.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 626