I heard the Messenger of Allah ﷺ say this: Ablution is obligatory (for one who takes anything) touched by fire. (Using translation from Muslim 351)  

سَمِعْتُ رَسُولَ اللَّهِ يَقُولُ «الْوُضُوءُ مِمَّا مَسَّتِ النَّارُ» قِيلَ لِأَبِي مُحَمَّدٍ تَأْخُذُ بِهِ؟ قَالَ لَا