John Lightfoot on Luke 17:7

[Will say unto him by and by, Go and sit down to meat?] Some there were of old that were wont to do thus. "The wise men of old were used to give their servant something of every thing that they ate themselves." This was indeed kindly done, and but what they ought; but then it follows, they made their beasts and their servants take their meals before themselves. This was supererogation.