proverb

[stevenflett]

Where does the saying never look a gift horse in the mouth come from?

[shaneystar2]

This proverb is based on the fact that a horse's value is determined by his age, which, in turn, can be roughly determined by an examination of his teeth. The message conveyed is that a gift should be appreciated for the thought and spirit behind it, not according to its value. St. Jerome, who never accepted payment for his writings, first used the phrase in reply to his literary critics. His exact words: "Never inspect the teeth of a gift horse."

[porlock]

Yes, it is credited to St Jerome. It is found in his 'On the Epistle to the Ephesians'. In the original Latin: 'Noli equi dentes inspicere donati'.