The narration is traced back to the Prophet ﷺ, who said, "The merciful are shown mercy by the Most Merciful. Show mercy to those on earth, and the One in the heavens will show mercy to you."Musaddad did not say "the freed slave of Abdullah bin Amr," and he said, "The Prophet ﷺ said."
حدثنا أبو بكر بن أبي شيبة ومسدد المعنى قالا حدثنا سفيان عن عمرو عن أبي قابوس مولى لعبد الله بن عمرو
يبلغ به النبي ﷺ الراحمون يرحمهم الرحمن ارحموا أهل الأرض يرحمكم من في السماء لم يقل مسدد مولى عبد الله بن عمرو وقال قال النبي ﷺ
[Its isnad is hasan] Tirmidhi narrated it in the Book of Righteousness and Kinship Ties, chapter on what has been said about mercy to people, hadith no. 1924, from the hadith of Sufyan bin Uyayna, with this wording, and he explicitly stated that he heard it directly. Tirmidhi said, "Hasan sahih." It is also found in Musannaf Ibn Abu Shayba, 8/338. Hakim graded it sahih, 4/159, and Dhahabi agreed with him.