سنن النسائي

It was narrated that Umm Salamah said: "I heard the Messenger of Allah (ﷺ) say: 'When you see the dead, say something good, for the angels say Amin to whatever you say; When Abu Salamah died, I said: 'O Messenger of Allah, what should I say?' He said: 'Say" Allahummaghfirlanaa wa lahu wa a 'qibni minhu 'uqbai hasanah (O Allah, forgive us and him, and compensate me well for this loss.)"' Then Allah, the Mighty and Sublime, compensated me with Muhammad."