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: "There is no prayer for the one who has not performed ablution, and there is no ablution for the one who has not said 'Bismillah' (in the name of Allah)."
(b) Imam Ahmad bin Hanbal (may Allah have mercy on him) was asked about saying 'Bismillah' (in the name of Allah) before ablution, and he said: I do not know of any established hadith on it; the strongest thing in it is the hadith of Kathir bin Zayd from Rubayh, and Rubayh is an unknown person.
(c) Imam al-Tirmidhi (may Allah have mercy on him) reports from Imam al-Bukhari (may Allah have mercy on him) that he said: In my view there is no narration in this chapter better than the hadith of Rabah bin Abd al-Rahman.
(d) Abu Bakr bin Huwaytib narrates it from the Prophet (peace and blessings be upon him) as a mursal report.
(e) The Shaykh says: Abu Thifal is not well known.
(f) Imam al-Bukhari (may Allah have mercy on him) says that in the chain of al-Laythi from Sayyiduna Abu Hurayrah (may Allah be pleased with him) about saying 'Bismillah' (in the name of Allah), it is not established that Salamah heard from Sayyiduna Abu Hurayrah (may Allah be pleased with him), nor that Ya'qub heard from his father.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 195