Sunan at-Tirmithiy كتاب الطهارة باب جاء أن مسح الرأس مرة
Ar-Rubaiy' Bint-Mu'awwith Ibn-'Afrā' saw the Prophet, peace and blessings of God be upon him, performing ablution. She said, "He wiped his head front to back, then back to front, and wiped his temples and ears once." Click on ḥadīth to read more