Sunan Ibn Majah, Book 1, Hadith 525 (In-Book) ⓘ

It was narrated that Anas bin Malik would place his hands over his ears and say: "May my ears be made deaf, if I did not hear the messenger of Allah saying: 'Perform ablution after (eating) that which has been changed by fire.'"

حَدَّثَنَا هِشَامُ بْنُ خَالِدٍ الأَزْرَقُ، حَدَّثَنَا خَالِدُ بْنُ يَزِيدَ بْنِ أَبِي مَالِكٍ، عَنْ أَبِيهِ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كَانَ يَضَعُ يَدَيْهِ عَلَى أُذُنَيْهِ وَيَقُولُ صُمَّتَا إِنْ لَمْ أَكُنْ سَمِعْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَقُولُ ‏ "‏ تَوَضَّئُوا مِمَّا مَسَّتِ النَّارُ ‏" ‏ ‏.‏