Hadith: The Prophet (may Allah's peace and blessings be upon him) performed ablution and passed a wet hand on his forelock, over the turban, and over the two leather socks

عن المغيرة بن شعبة رضي الله عنه : أن النبي صلى الله عليه وسلم توضأ، فمسح بِنَاصِيَتِهِ، وعلى العِمَامة والخُفَّين.
[صحيح] - [رواه مسلم]

Al-Mughīrah ibn Shu‘bah (may Allah be pleased with him) reported: The Prophet (may Allah's peace and blessings be upon him) performed ablution and passed a wet hand on his forelock, over the turban, and over the two leather socks.
Sahih/Authentic. - [Muslim]

Explanation

Al-Mughīrah ibn Shu‘bah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) wiped over his forelock, which is the front of his head at the hairline, then he completed the wiping over his turban. He did not suffice with wiping part of his head; rather, he completed wiping his head by wiping over the turban. From the Prophet's guidance as well is wiping over the leather socks, as mentioned in this Hadīth and others.