What is the authenticity of the hadith: "By Him in whose hand is my soul, Allah does not bestow His mercy except upon one who is merciful," which is interpreted as showing mercy to all people?

Allah does not bestow His mercy except upon those who are merciful. The Prophet, peace and blessings be upon him, explained this to mean that mercy is not exclusive to relatives or friends, but encompasses all people. It is stated in the Hadith: "Be merciful to those on earth, and the One in the heaven will be merciful to you." This includes all creatures, both humans and animals.