You must observe the Islamic State’s idea of morality, or they will kill you, which they consider to be a moral act.

The Islamic State statement quotes the Qur’an: “O you who believe! Take not the Jews and the Christians as Auliya’ (friends, protectors, helpers), they are but Auliya’ of each other. And if any amongst you takes them (as Auliya’), then surely he is one of them. Verily, Allah guides not those people who are the Zalimun (polytheists and wrong-doers and unjust)” (5:51)

Not that this has anything to do with Islam!

“Celebrating New Years amounts to practising idolatry says Islamic State,” by Vicky Nanjappa, OneIndia.com, January 1, 2017: