Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 17:7-10

“Because faith makes its possessor a keeper of God’s commandments, and adorns him with wonderful works; it would seem from thence that a man might thereby fall into the sin of pride. Our Lord therefore forewarned His Apostles by a fit example, not to boast themselves in their virtues, saying, But which of you having a servant plowing, &c.”