Not to look at gift horse in the mouth

Question

I understand the meaning of the saying and the context it’s used in.

What I don’t understand is why you would look a horse (or gift horse) in the MOUTH. What is special about its mouth?

In: Other

Answer 1

Looking at a horses teeth is a way of aging them, so the idea of don’t look a gift horse in the mouth is along the lines of don’t nitpick over the detail of a free offer!