Charles Ellicott Commentary Mark 9:5

"And Peter answereth and saith to Jesus, Rabbi, it is good for us to be here: and let us make three tabernacles; one for thee, and one for Moses, and one for Elijah." — Mark 9:5 (ASV)

Master.—St. Mark, characteristically, gives the Hebrew “Rabbi” for the “Lord” of St. Matthew, and the “Master” of St. Luke.