Tafsir of Al-Kahf 18:106

ذلك جزاوهم جهنم بما كفروا

That shall be their recompense, Hell; because they disbelieved, means, `We will punish them with that because of their disbelief and because they took the signs and Messengers of Allah as a joke, mocking them and disbelieving them in the worst way.'

واتخذوا آياتي ورسلي هزوا

and took My Ayat and My Messengers for jest.''