Sitting in church

Before I began serving in the altar at Holy Trinity, when I was tired, I would sit, usually on the floor, during the Divine Liturgy.  After I began serving, Fr. Vladimir would not let me sit.  He told me something that I've never forgotten, and often heard repeated: "You cannot sit in church unless you are a bishop, or old, or sick, or pregnant."

Then he added "You are not a bishop, you are not old, and you are not pregnant.  If you are too sick to stand, you should not be in church."