Hammad bin Zayd حماد بن زيد بن درهم الأزدي الأزرق · The Book of the Sunnah

The Messenger of Allah (ﷺ) said: "Whoever innovates something in this matter of ours (i.e. Islam) that is not part of it, will have it rejected."

"I heard the Messenger of Allah (ﷺ) say: 'The affairs of the Children of Israel remained fair until Muwalladun emerged among them - the children of female slaves from other nations. They spoke of their own opinions (in religious matters) and so they went astray and led others astray.'"

"One day the Prophet (ﷺ) appeared among the people. A man came to him and said: 'O messenger of Allah, what is Iman (faith)?' He said: 'To believe in Allah, His angels, His books, His Messengers and the meeting with, and to believe in the Final Resurrection.' He said: 'O Messenger of Allah, what is Islam?' He said: 'To worship Allah (alone) and not to associate anything with Him; to establish the prescribed prayers, to pay the obligatory Zakat, and…

"I heard Abu Hurairah narrating that the Prophet (ﷺ) said: 'Adam and Musa debated, and Musa said to him: "O Adam, you are our father but have deprived us and caused us to be expelled from Paradise because of your sin." Adam said to him: "O Musa, Allah chose you to speak with, and he wrote the Tawrah for you with His own Hand. Are you blaming me for something which Allah decreed for me forty years before He created…