ENOfficial
Umm Salama reported God’s messenger as saying, “When you are with one who is ill or dying speak good words, for the angels say Amen to what you say.” Muslim transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أُمِّ سَلَمَةَ قَالَتْ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا حَضَرْتُمُ الْمَرِيضَ أَو الْمَيِّت فَقولُوا خيرا فَإِن الْمَلَائِكَةَ يُؤَمِّنُونَ عَلَى مَا تَقُولُونَ» . رَوَاهُ مُسْلِمٌ
sunnah.com