Sayyiduna Mu'awiyah bin Haydah (may Allah be pleased with him) narrated: I came to the Messenger of Allah (peace and blessings be upon him) and said: "By Allah! I did not come to you until I had sworn oaths as many as these fingers of mine that I would neither follow you nor follow your religion. And I have come (to you) as a man who understands nothing except what Allah, the Mighty and Majestic, and His Messenger (peace and blessings be upon him) teach me. And I ask you by Allah: with what has your Lord sent you to us?" He (peace and blessings be upon him) said: "Sit down." Then he said: "With Islam." I said: "What is the sign of Islam?" He (peace and blessings be upon him) said: "That you bear witness that there is no true deity except Allah and that Muhammad (peace and blessings be upon him) is the Messenger of Allah, that you establish the prayer, pay the zakah, and separate yourself from shirk (associating partners with Allah). Every Muslim is inviolable to another Muslim; they are two brothers who help one another. Allah does not accept any deed from a polytheist who associates partners with Him after his Islam. My Lord will summon me and ask me: 'Did you convey (the message) to My servants?' So let those of you who are present convey it to those who are absent. You will be summoned with your mouths sealed, and the first thing about which each of you will be asked is his thigh and his palm." I said: "O Messenger of Allah! Is this our religion?" He (peace and blessings be upon him) said: "Yes, and you will indeed be gathered on your faces, on your feet, and riding."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17018