Musnad Ahmad 31:523

Waki' narrated to us, Ali ibn Mubarak narrated to us, from Yahya ibn Abi Kathir, from Iyad ibn Hilal, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If the devil comes to one of you in his prayer and says: 'You have broken your ablution,' then let him say: 'You have lied,' as long as he does not find a smell with his nose or hear a sound with his ear."