The Messenger of Allah ﷺ said to me, "Kaab bin Ujra, prayer is a proof, fasting is a strong shield, and charity extinguishes sin just as water extinguishes fire. Kaab bin Ujra, no flesh that grows from unlawful sustenance will thrive, but the Fire is more deserving of it." The hadith continues.
قال لي رسول الله ﷺ: يا كعب بن عجرة! الصلاة برهان والصوم جنة حصينة والصدقة تطفئ الخطيئة كما يطفئ الماء النار يا كعب بن عجرة! إنه لا يربو لحم نبت من سحت إلا كانت النار أولى به الحديث.
Tirmidhi (614) narrated it from Abdullah bin Ziyad Qatwani Kufi, who said, "Ubaydullah bin Musa related to us, Ghalib Abu Bishr related to us, from Ayub bin Aaidh Tai, from Qays bin Muslim, from Tariq bin Shihab, from Kaab bin Ujra," and he mentioned it in a lengthy passage.Tirmidhi said, "This is a hasan gharib hadith by this route. We do not know it except through the narration of Ubaydullah bin Musa. Ayub bin Aaidh is considered daif, and it is said that he held the view of Irja. I asked Muhammad, meaning Bukhari, about this, and he did not know it except through the narration of Ubaydullah bin Musa, and he considered it very unusual (gharib)."I say, its chain of transmission is hasan because of Ghalib Abu Bishr. Ibn Main deemed him reliable, and Ibn Hibban mentioned him among the reliable narrators in his book, and he is a hasan al-hadith narrator. As for Ayub bin Aaidh, most scholars affirm his reliability.