He teaches us that we are ALL servants of each other, even Jesus Himself!
Those Corporal Works of Mercy we've been learning about all year... even here, in His last moments, Jesus is serving others and reminding his Apostles to do the same.
The highlight of Holy Thursday Mass each year is the washing of feet. Father, like Jesus, removes his chasuble (that's the big vestment that goes over the rest), and washes the feet of several people. Since his first Holy Thursday as pope, Pope Francis has chosen to go out to prisons, refugee camps, and hospitals to wash people's feet, reminding us that Jesus asked us to care for "the least of my brothers and sisters."
(Of course, with Covid still being a factor, the washing of feet will be a little different this year!)