Holy Thursday also known as Maundy Thursday celebrates the institution of the Eucharist as the true body and blood of Jesus Christ and the institution of the sacrament of the priesthood.
One of the traditions on Holy Thursday is the washing of the feet of laymen by their priest during the Mass of the Lord’s Supper, which recalls Christ’s own washing of the feet of His disciples.
When he had washed their feet, and taken his garments, and resumed his place, he said to them, “Do you know what I have done to you? You call me Teacher and Lord; and you are right, for so I am. If I then, your Lord and Teacher, have washed your feet, you also ought to wash one another’s feet. For I have given you an example, that you also should do as I have done to you. (John 13:12-15)