At the Last Supper, Jesus washed all the disciple’s feet (John 13). Peter, who deeply respected Jesus, didn’t want to allow his Master to wash his feet. But Jesus was adamant to do this, and set an example for them to follow. In Luke 22:24-30, Jesus demonstrates the same idea by settling an argument:
24An argument broke out among the disciples as to which one of them should be thought of as the greatest. 25 Jesus said to them, “The kings of the pagans have power over their people, and the rulers claim the title ‘Friends of the People.’ 26 But this is not the way it is with you; rather, the greatest one among you must be like the youngest, and the leader must be like the servant.27 Who is greater, the one who sits down to eat or the one who serves? The one who sits down, of course. But I am among you as one who serves.
28 “You have stayed with me all through my trials; 29 and just as my Father has given me the right to rule, so I will give you the same right. 30 You will eat and drink at my table in my Kingdom, and you will sit on thrones to rule over the twelve tribes of Israel.
How much this teaching flies in the face of the Pharisees, who felt such a sense of entitlement: Outwardly looking as though they were obeying the law to the letter, and condemning everyone else at the same time. Jesus, the greatest of all, stooped to the role of a servant. Let’s do the same by serving God and serving our neighbours in His name.
Perhaps for the same reason Jesus highlighted two commandments as the most important: Love the Lord with all your heart, soul, mind and strength, and love your neighbour as yourself.