It is narrated from Sayyiduna Abdullah bin Ukaym (may Allah be pleased with him): A letter of the Messenger of Allah (peace and blessings be upon him) was read out to us, and it said: "Do not benefit from the skin of a dead animal, nor from its sinews."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 41
It is narrated from Sayyiduna Abdullah bin Ukaym (may Allah be pleased with him): A letter of the Messenger of Allah (peace and blessings be upon him) was read out to us in the land of Juhaynah, when I was a young man, and it was written in it: "Do not make use of the skin of a dead animal, nor of its sinews."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 42
(a) Some people came to Sayyiduna Abdullah bin Ukaym (may Allah be pleased with him), and he told them that the Messenger of Allah (peace and blessings be upon him) wrote to the people of the tribe of Juhaynah one month before his death: "Do not benefit from the skin of a dead animal, nor from its sinews."
(b) Imam al-Bayhaqi (may Allah have mercy on him) said: This hadith has also come through another chain, whose wording is that he (peace and blessings be upon him) wrote this letter forty days before his death. It is narrated from Sayyiduna Abdullah bin Ukaym (may Allah be pleased with him): The elders of our tribe Juhaynah told us that the Prophet (peace and blessings be upon him) wrote to them. This will be mentioned later, if Allah wills.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 43
Yahya bin Ma'in (may Allah have mercy on him) said that the hadith of Abdullah bin Ukaym (may Allah be pleased with him), "The letter of the Messenger of Allah (peace and blessings be upon him) came to us (in which it was written): Do not benefit from the skin of a dead animal, nor from its sinews", has been narrated to us by our companions with another strong chain, that the Prophet (peace and blessings be upon him) wrote: "Do not benefit."
Al-Shaykh (al-Bayhaqi) (may Allah have mercy on him) said: By this, Abu Zakariya (may Allah have mercy on him) meant to point out a hidden defect ('illah) in this hadith; and according to us, it is understood as referring to (the skin) before tanning. The evidence for this is the hadith narrated (with) authentic (chains) in the following chapters.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 44