It was narrated that 'Abdullah bin 'Amr bin 'As said:"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

English translation · Sunan Ibn Majah