Augustine of Hippo — as excerpted in the Catena Aurea on John 20:10-18

“(Tr. cxxi) Or she first turned her body, but thought Him what He was not; now she was turned in heart, and knew who He was. Let no one however blame her, because she called the gardener, Lord, and Jesus, Master. The one was a title of courtesy to a person from whom she was asking a favour; the other of respect to a Teacher from whom she was used to learn to distinguish the divine from the human. The word Lord is used in different senses, when she says, They have taken away my Lord, and when she says, Lord, if Thou have borne Him away.”