Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.044A.
It is allowed to wipe over slippers, as this has been related from many companions. Says Abu Dawud, “Wiping over sandals (has been done by) ‘Ali ibn Abu Talib, Ibn Mas’ud, al-Barra’ ibn ‘Aazib, Anas ibn Malik, Abu Umamah, Sahl ibn Sa’d and ‘Amr ibn Hareeth. It has also been related from ‘Umar ibn al-Khattab and Ibn ‘Abbas.” ‘Ammar, Bilal ibn ‘Abdullah ibn Abu Aufi and Ibn ‘Umar also have hadith on this subject. In Ibn alQayyim’s Tahzhib as-Sunan, he relates from Ibn al-Munzhir, “Ahmad made a statement about the permissibility of wiping over slippers because of his fairness and justice. Nevertheless, the basis of this permissibility is the practice of the companions and a manifest analogy. There is no real difference between socks and slippers. It is correct that they take the same ruling. Most scholars say that one can wipe over either one.” Those who permit it include Sufyan al-Thauri, Ibn al-Mubarak, ‘Ata, al-Hasan and Sa’eed ibn alMusayyab. Commenting on this subject, Abu Yusuf and Muhammad said, “It is allowed to wipe over them if they are thick and completely hide what they cover.”
Abu Hanifah did not approve of wiping over thick slippers, but he changed his mind three or seven days before his death. He wiped over his slippers during his illness and said to his visitors, “I did what I used to tell people not to do.” Al-Mughirah ibn Shu’bah reported that the Messenger of Allah, upon whom be peace, made ablution and wiped over his socks and slippers. This is related by Ahmad, at-Tahawi, Ibn Majah and at-Tirmizhi, who called it hassan sahih. Abu Dawud graded it weak.2
As it is permissible to wipe over socks so is it permissible to wipe over any foot covering, which has been used to avoid the cold or protect the wound, and so on. Of its permissibility, Ibn Taimiyyah says, “It is all right to wipe over foot covering because it takes precedence over wiping socks or slippers, for usually a foot covering is used for some need and to protect the feet from some harm. If wiping over the socks and slippers is allowed, then wiping over any foot covering should come first. Whoever claims that there is a consensus on the inadmissibility of wiping over foot coverings does so with a lack of knowledge. Not to speak of a consensus, he cannot prove its forbiddance even from the works of ten famous scholars.” He goes on to say, “Whoever ponders over the words of the Messenger of Allah, upon whom be peace, and gives analogy its proper place, will know that the license from him was spacious on this subject and in accord with the beauty of Islamic law and the monotheistic magnanimity with which the Prophet had been sent.” Even if there are some holes or cuts in the socks, it is permissible to wipe over them, as long as the person has only such socks to wear. Says al-Thauri, “The slippers of the emigrants and helpers were not free of cuts or holes, like the slippers of the people (in general). If this were a matter of concern, it would have been mentioned and related by them.”