Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that a Bedouin from Banu Sa'd bin Bakr came to the Messenger of Allah (peace and blessings be upon him) and said: Peace be upon you, O lad of Banu Abd al-Muttalib. The Prophet (peace and blessings be upon him) said: "And upon you be peace." He said: I am a man from your maternal relatives, from Banu Sa'd bin Bakr, and I am the envoy and delegate of my people to you. I will ask you and be harsh in my questioning, and I will adjure you and be stern in my adjuring. The Prophet (peace and blessings be upon him) said: "Go ahead, O brother of Banu Sa'd." He said: Who created you, who created those before you, and who will be the Creator of those after you? He (peace and blessings be upon him) said: "Allah." He said: Then I adjure you by Him: Is it He who sent you? He (peace and blessings be upon him) said: "Yes." He said: Tell me, who created the seven heavens and the seven earths and made provision flow between them? He (peace and blessings be upon him) said: "Allah." He said: I adjure you by Him: Is it He who sent you? He (peace and blessings be upon him) said: "Yes." He said: We have found in your letter, and your messengers have commanded us, that we should offer five prayers by night and day at their appointed times. I adjure you by Him: Is it He who commanded you? He (peace and blessings be upon him) said: "Yes." He said: We have found in your letter, and your messengers have commanded us, that we should fast the month of Ramadan. I adjure you by Him: Is it He who commanded you? He (peace and blessings be upon him) said: "Yes." He said: We have found in your letter, and your messengers have commanded us, that you should take from the surplus of our wealth and distribute it among our poor. I adjure you by Him: Is it He who commanded you? He (peace and blessings be upon him) said: "Yes." He said: As for the fifth matter, I do not ask about it, nor do I have any desire for it (meaning acts of indecency). Then he said: By the One who sent you with the truth, I will act upon this, and so will whoever of my people obeys me. Then he went back, and the Messenger of Allah (peace and blessings be upon him) laughed until his (peace and blessings be upon him) molar teeth became visible, then said: "If he is truthful, he will surely enter Paradise."
Hadith Referenceالمعجم الكبير للطبراني / باب الضاد / 8120