سنن النسائي

It was narrated from 'Amr bin Maimun from "Abdullah bin Rubayy'ah As-Sulami, who was also one of the Companions of Allah's Messenger (ﷺ) from 'Ubaid bin Khalid As-Sulami, that: the Messenger of Allah (ﷺ) established the bond of brotherhood between two men. One of them was killed and the other died after him. We offered the funeral prayer for him, and the Prophet (ﷺ) said: "What did you say?" They said: "O Allah, forgive him; O Allah, have mercy on him; O Allah, join him with his companion." The Prophet (ﷺ) said: "Where is his Salah in comparison to his companion's Salah? Where are his deeds in comparison to his companion's deeds? Indeed the difference between heaven and Earth." (One of narrators) 'Amr bin Maimun Said: "I was happy with that because he raised it for me."