It is reported from ʿAbdullāh b. Mas’ūd – Allāh be pleased with him – that he said:

“One should get used to the idea that if everyone on Earth disbelieved, you would not disbelieve. Do not be an im’ah (characterless).” He was asked, “And what is an im’ah?” He replied, “A person who says, ‘I am with the people (I do what they do).’ Verily, there is to be no following examples in evil.”

Ibn Battah, Al-Ibānah Al-Kubrā Vol.1 p33.