It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When a dog laps from your vessel, wash it seven times, the first time with earth."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1143
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When a dog laps from the vessel of one of you, wash it seven times, the first or the last time with earth."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1145
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "When a dog puts its mouth into a vessel, it should be washed seven times, and the seventh time with dust."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1146
Qatadah (may Allah have mercy on him) narrated the like of it with the same chain, except that he said: "The first time it should be washed with dust."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1147
(a) It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him): "When a dog puts its mouth into a vessel, wash it seven times, and the first time (it should be washed) with dust."
(b) Sayyiduna Abdullah bin Mughaffal (may Allah be pleased with him) also mentions dust from the Prophet (peace and blessings be upon him).
This hadith is gharib (unusual); if Mu'adh preserved it accurately, then it is hasan (good), because the mention of dust in this hadith was not narrated by any trustworthy narrator other than Ibn Sirin from Abu Hurayrah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1148
It is narrated from Sayyiduna Abdullah bin Mughaffal (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) ordered the killing of dogs, then said: "I have no concern with dogs." And he (peace and blessings be upon him) granted a concession for the hunting dog and the dog that guards goats, and said: "When a dog puts its mouth into a vessel, wash it seven times, and the eighth time clean it with dust."
Sayyiduna Abu Hurayrah (may Allah be pleased with him) was the most retentive of those who narrated hadith in his time, so his narration takes precedence. Hammad bin Zayd narrated, from Ayyub, from Muhammad bin Sirin, the fatwa of Sayyiduna Abu Hurayrah (may Allah be pleased with him) of seven (washings), just as he narrated it; and this indicates the error of the narration of Abd al-Malik bin Abi Sulayman, from Ata, from Sayyiduna Abu Hurayrah (may Allah be pleased with him), of three (washings). What Abd al-Malik narrates in contradiction to the trustworthy narrators is not accepted. And success is from Allah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1149