The Messenger of Allah ﷺ said, "There has never been a prophet whom Allah sent to a nation before me without his having from his nation devoted disciples and companions who followed his way and adhered to his command. Then there came after them successors who said what they did not do, and did what they were not commanded. Whoever struggles against them with his hand is a believer, whoever struggles against them with his tongue is a believer, and whoever struggles against them with his heart is a believer. Beyond that, there is not even a mustard seed of faith."
أن رسول الله ﷺ قال: ما من نبي بعثه الله في أمة قبلي إلا كان له من أمته حواريون وأصحاب، يأخذون بسنته، ويقتدون بأمره، ثم إنها تخلف من بعده خلوف يقولون ما لا يفعلون، ويفعلون ما لا يؤمرون، فمن جاهدهم بيده فهو مؤمن، ومن جاهدهم بلسانه فهو مؤمن، ومن جاهدهم بقلبه فهو مؤمن، وليس وراء ذلك من الإيمان حبة خردل.
Muslim narrated it in the Book of Faith (80:50) through various routes from Yaqub bin Ibrahim bin Saad, [who said] my father narrated to me, from Salih bin Kaysan, from Harith, from Jafar bin Abdullah bin Hakam, from Abdul-Rahman bin Miswar, from Abu Rafi, from Abdullah bin Masud, and he related it.