The Messenger of Allah ﷺ said, "Whoever sends blessings upon me once, Allah will send blessings upon him tenfold."
أن رسول الله ﷺ قال: من صلى علي واحدة صلى الله عليه عشرا.
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Muslim narrated it in the Book of Prayer (408) through several routes from Ismail bin Jafar, from Ala bin Abdul-Rahman, from his father, from Abu Hurairah, as mentioned.Ahmad also narrated it (7561), and Ibn Hibban graded it sahih (905), both of them through the route of Abdul-Rahman bin Ishaq, from Ala bin Abdul-Rahman, with the wording, "Whoever sends blessings upon me once, Allah, Mighty and Majestic, will record for him ten good deeds because of it."