ENOfficial
-- The Prophet (ﷺ) said: "No one sends greetings (or prayers of peace) upon me but Allah returns my soul to me so that I may return his greetings." Reference: Abu Dawud (no. 2041). Al-Albani graded it good in Sahih Abu Dawud 1/383.
Source: sunnah.com
Other translations
Arabic
وَقَالَ صلى الله عليه وسلم: (مَا مِنْ أَحَدٍ يُسَلِّمُ عَلَيَّ إِلاَّ رَدَّ اللَّهُ عَلَيَّ رُوحِيَ حَتَّى أَرُدَّ عَلَيْهِ السَّلاَمَ)
sunnah.com