ENOfficial
‘Umar b. al-Khattab reported God’s messenger as saying, “When you visit an invalid tell him to make supplication for you, for his supplication is like that of the angels.” Ibn Majah transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ عُمَرَ بْنِ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ قَالَ ك قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا دَخَلْتَ عَلَى مَرِيضٍ فَمُرْهُ يَدْعُو لَكَ فَإِنَّ دُعَاءَهُ كَدُعَاءِ الْمَلَائِكَةِ» . رَوَاهُ ابْنُ مَاجَهْ
sunnah.com