Cyprian of Carthage, Three Books of Testimonies Against the Jews III.52: That no one should be uplifted in his labour

In Solomon, in Ecclesiasticus: “Extol not thyself in doing thy work.” Also in the Gospel according to Luke: “Which of you, having a servant ploughing, or a shepherd, says to him when he cometh from the field, Pass forward and recline? But he says to him, Make ready somewhat that I may sup, and gird thyself, and minister to me, until I eat and drink; and afterwards thou shalt eat and drink? Does he thank that servant because he has done what was commanded him? So also ye, when ye shall have done that which is commanded you, say, We are unprofitable servants; we have done what we had to do.”