It is narrated about Sayyiduna Abu Ayyub (may Allah be pleased with him) that he used to instruct people to wipe over leather socks (khuffs) but would himself wash his feet. He was asked about this, and he said: "What a poor share that would be for me, if its benefit were yours and its sin were upon me! I saw the Messenger of Allah (peace and blessings be upon him) wiping over the leather socks and instructing people to do so, but ablution (wudu) has been made dear to me."
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3967