SectionConditions for wiping over khuffs and socks
The first condition: Wearing them after complete purification
The Muslim performs a complete wudu with water and washes his feet up to the ankles, then wears the khuffs or socks while in a state of purification. Wearing them after tayammum is not sufficient, because the concession is established for the one who placed his feet into them after water-based purification. The evidence is the Prophet's statement to al-Mughirah, may Allah be pleased with him:
"Leave them, for I put them on while they were pure."
It is safer to complete the entire wudu before wearing either sock, to avoid disagreement. If he wore them without wudu, or wore them before washing the feet, it is not permissible for him to wipe over them after breaking wudu.
The second condition: They cover the feet along with the ankles
The khuff or sock should cover the area that is obligatory to wash, meaning the whole foot along with the ankles. The ankles are the two protruding bones at the joint of the leg; they are not the heels. Therefore, wiping over a short sock that falls below the ankles and exposes them is not valid.
The third condition: They are pure
One does not wipe over a khuff or sock that is impure and then pray with impurity. If impurity gets on it and the place of impurity can be purified while the khuff or sock remains on, then the impurity must be removed before prayer.
The fourth condition: Wiping is for minor impurity
Wiping over khuffs and socks is done in wudu from minor impurity, such as urine, stool, passing wind, or deep sleep. As for janabah and anything that requires ghusl, wiping is not sufficient. Rather, the khuffs or socks must be removed and the feet washed with the rest of the body.
From Safwan ibn Assal, may Allah be pleased with him:
"The Messenger of Allah, peace and blessings be upon him, used to command us, when we were traveling, not to remove our khuffs for three days and their nights, except from janabah, but from stool, urine, and sleep."
Narrated by al-Tirmidhi, al-Nasa'i, and Ibn Majah, and authenticated by a group of scholars.
The fifth condition: Observing the legal duration
The resident wipes for one day and night, meaning twenty-four hours, and the traveler wipes for three days and their nights, meaning seventy-two hours.
From Shurayh ibn Hani', may Allah have mercy on him:
"I came to Aishah to ask her about wiping over the khuffs. She said: Go to Ibn Abi Talib and ask him, for he used to travel with the Messenger of Allah, peace and blessings be upon him. So we asked him, and he said: The Messenger of Allah, peace and blessings be upon him, appointed three days and their nights for the traveler, and one day and night for the resident."
Narrated by Muslim.