That the socks or leather boots be pure

Therefore, wiping over what is ritually impure is not valid; because wiping over impurity only increases the filth and defiles the hand that touched the impurity; and because a person usually wipes in order to pray, and there is no prayer in something that is ritually impure.And the evidence that there is no prayer in something that is ritually impure: (That the Messenger of Allah (peace and blessings be upon him) was one day praying with his companions, so he took off his sandals, and the companions took off their sandals,So when he finished the prayer, he asked them: Why did you take off your sandals?They said: We saw you take off your sandals, so we took off our sandals,So he said: Indeed, Jibril came to me and informed me that there was filth in them) Meaning: that he took them off for that reason, and this indicates that what is worn must be pure.