Whoever cheats us is not one of us

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) passed by a man who was selling grain. The grain outwardly pleased him (peace and blessings be upon him), so he (peace and blessings be upon him) put his blessed hand into it, and the grain was wet inside. Then the Prophet (peace and blessings be upon him) said: "Whoever deceives us is not one of us."
This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs did not record it in this way. It has also been narrated from al-Ala' by Muhammad and Isma'il (the sons of Ja'far bin Abi Kathir).

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) came to the market and saw a heap of grain. He (peace and blessings be upon him) put his blessed hand into it and found moisture. Then he (peace and blessings be upon him) said: "Beware! Whoever deceives us is not one of us."

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) passed by a heap of grain. He (peace and blessings be upon him) put his hand into it, and his (peace and blessings be upon him) fingers were touched by wetness. He (peace and blessings be upon him) asked: "O owner of the grain, what is this?" He said: O Messenger of Allah, rain from the sky fell on it. He (peace and blessings be upon him) said: "Then why did you not put this wet part on top of the grain so that people could see it?" Then he (peace and blessings be upon him) said: "Whoever deceives is not of me (not upon my way)." Imam Muslim has recorded the narration of Suhayl from his father from Sayyiduna Abu Hurayrah (may Allah be pleased with him) with the words: "Whoever deceives us is not one of us." However, the two Shaykhs did not record all these details of the incident found in these hadiths; nevertheless, all these narrations are sahih (authentic) on the condition of Imam Muslim.
All these hadiths are sahih on the condition of Imam Muslim.

Umayr bin Sa'id narrates from his paternal uncle (Sayyiduna al-Harith bin Suwayd (may Allah be pleased with him)) that the Messenger of Allah (peace and blessings be upon him) went out to al-Baqi', and there he (peace and blessings be upon him) saw grain being sold in sacks. He (peace and blessings be upon him) put his blessed hand into it and brought out something (moisture or a defect) that he (peace and blessings be upon him) disliked. Then he (peace and blessings be upon him) said: "Whoever deceives us is not one of us."
This hadith is sahih (authentic), and the paternal uncle of Umayr bin Sa'id is al-Harith bin Suwayd al-Nakha'i.

It is narrated from Abu Siba' that he said: I bought a she-camel from the house of Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him). When I set off with it, Sayyiduna Wathilah came after me (hurriedly), dragging his lower garment, and asked: O servant of Allah, have you bought it? I said: Yes. He asked: Were you told everything about it (its defects and faults)? I said: What defect could it have? It is outwardly quite fat and healthy. He asked: Did you buy it for travel or for meat? I said: I bought it for Hajj. He said: Then return it. At this the (former) owner of the she-camel said: May Allah set you right, is your aim only to spoil my sale? Sayyiduna Wathilah (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "It is not lawful for anyone to sell anything unless he makes clear the (defect) in it, and it is not lawful for anyone who knows of (that defect) (to remain silent) unless he makes it clear."
The chain of this hadith is sahih (authentic), but the two Shaykhs did not record it.

Jumay' bin Umayr narrates from his maternal uncle, Sayyiduna Abu Burdah (may Allah be pleased with him), that the Messenger of Allah (peace and blessings be upon him) was asked which earning is the purest or the most excellent. He (peace and blessings be upon him) said: "A man's labour with his own hand, and every trade that is based on righteousness and truthfulness."

Sa'id bin Umayr narrates from his paternal uncle (Sayyiduna al-Bara' bin Azib (may Allah be pleased with him)) that the Messenger of Allah (peace and blessings be upon him) was asked which earning is the most excellent. He (peace and blessings be upon him) said: "Trade that is based on righteousness and truthfulness."
The chain of this hadith is sahih (authentic), but the two Shaykhs did not record it. Wa'il bin Dawud and his son Bakr bin Wa'il are both trustworthy (thiqah). Yahya bin Ma'in has stated explicitly that the paternal uncle of Sa'id bin Umayr is al-Bara' bin Azib. And when the narrations of Sufyan al-Thawri and Sharik differ, the judgement goes in favour of Sufyan al-Thawri.

Abayah bin Rafi' bin Khadij narrates from his father (Sayyiduna Rafi' bin Khadij (may Allah be pleased with him)) that it was said: O Messenger of Allah, which earning is the purest? He (peace and blessings be upon him) said: "A person's working with his own hand, and every trade that is based on righteousness and honesty."
This is a third variation in the narration of Wa'il bin Dawud; however, the two Shaykhs did not take narrations from al-Mas'udi, although he is truthful.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that a man seized his debtor over ten dinars and said: By Allah, I will not let you go until you pay me my due or bring a guarantor. The narrator said: So the Prophet (peace and blessings be upon him) became his guarantor. Then that man brought the amount (of gold) that he had promised, and the Prophet (peace and blessings be upon him) asked him: "Where did you get this gold from?" He said: From a mine. He (peace and blessings be upon him) said: "We have no need of it; there is no good in it." So the Messenger of Allah (peace and blessings be upon him) paid off his debt (on his own behalf).
The chain of this hadith is sahih (authentic), but the two Shaykhs did not record it.