Is the God of Islam Merciful?

In 2014, in a bombing raid on the militant group Islamic State of Iraq and Syria (ISIS), Jordanian air force pilot Muath al Kasasbeh crashed his plane near Raqqa in Syria. He was promptly captured and ISIS used the social media platform Twitter to crowdsource suggestions on how to execute him. Finally, they trapped him in a cage, doused it in gasoline and burned him alive.