Mishkat al-Masabih

Abdullah bin Mas’ud (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: “When the Children of Israel became involved in sins, their scholars forbade them, but when they did not desist, the scholars began to sit with them and eat and drink with them. Allah made their hearts resemble one another, and cursed them on the tongue of Dawud and ‘Isa son of Maryam, and this happened because they disobeyed and transgressed.” The narrator says, the Messenger of Allah (peace and blessings be upon him) was reclining, then he sat up and said: “No (you will not succeed either), by the One in Whose hand is my soul! Until you strictly prevent them (the sinners, the wrongdoers).” And in the narration of Abu Dawud, he said: “Never, by Allah! You must certainly enjoin good, you must certainly forbid evil, you must certainly seize the hand of the wrongdoer, you must certainly incline him towards the truth, and you must certainly keep him established upon the truth, otherwise Allah will make your hearts resemble one another, then He will curse you as He cursed them.” Its chain is weak, narrated by al-Tirmidhi and Abu Dawud.