Sayyiduna Abdullah bin Busr (may Allah be pleased with him) narrates from his sister, who said that the Messenger of Allah (peace and blessings be upon him) said: "Do not fast on Saturday; if any of you finds nothing to eat, let him chew even a piece of wood."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8493
The son of Abdullah bin Busr (may Allah be pleased with him) narrates from his father, and he from his paternal aunt al-Samma' (may Allah be pleased with her), that the Messenger of Allah (peace and blessings be upon him) forbade fasting on Saturday and said: "If any of you finds nothing but a green stick, let him break his fast with it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8494
Al-Layth (may Allah have mercy on him) narrates from Ibn Shihab (may Allah have mercy on him) that whenever it was mentioned to him that fasting on Saturday had been forbidden, he would say: "This is a Himsi hadith."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8495
Al-Awza'i (may Allah have mercy on him) said: I kept concealing it, but then I saw that it had spread, meaning the hadith of Ibn Busr (may Allah be pleased with him) concerning fasting on Saturday.
(The hadith of Juwayriyah bint al-Harith (may Allah be pleased with her) has already passed in the previous chapter, which indicates that fasting on Saturday is permissible; it is as though what is meant by the prohibition is fasting on that day out of veneration for it.)
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8496
Kurayb, the freed slave of Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both), narrates that Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) and some people from among the Companions of the Prophet (peace and blessings be upon him) sent him to Sayyidah Umm Salamah (may Allah be pleased with her) to ask her about the days on which he (peace and blessings be upon him) most often fasted. She said: Saturday and Sunday. Then I returned to them and informed them, and it was as though they found it strange, so they all went to her (and said): We sent him to you for this matter, and he says that you (may Allah be pleased with her) said this. She said: He has spoken the truth; indeed the Messenger of Allah (peace and blessings be upon him) most often fasted on Saturday and Sunday, and he used to say: "These were days of festival for the polytheists, and I want to differ from them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8497