The ordinance of feet washing is not generally as accepted as the Lord’s Supper yet it is equally an ordinance.
It was delivered by Christ himself.
John 3: 1 – 17: 1.There was a man of the Pharisees, named Nicodemus, a ruler of the Jews: 2.The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him. 3. Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God. 4.Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother’s womb, and be born? 5.Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God. 6.That which is born of the flesh is flesh; and that which is born of the Spirit is spirit. 7.Marvel not that I said unto thee, Ye must be born again. 8.The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit. 9.Nicodemus answered and said unto him, How can these things be? 10.Jesus answered and said unto him, Art thou a master of Israel, and knowest not these things? 11.Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness. 12.If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things? 13.And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven. 14.And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up: 15.That whosoever believeth in him should not perish, but have eternal life. 16.For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. 17.For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
Christ dedicated it by example.
John 13: 17: If ye know these things, happy are ye if ye do them.