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 reported it in "the Prayer" (408) through several routes from Ismail bin Jafar, from Ala bin Abdul-Rahman, from his father, from Abu Hurairah, who mentioned it.Ahmad also reported it (7561), and Ibn Hibban graded it sahih (905), both through the route of Abdul-Rahman bin Ishaq, from Ala bin Abdul-Rahman, with the same chain, with the wording, "Whoever sends blessings upon me once, Allah will record for him ten good deeds because of it."