By the skin of one’s teeth

This expression first appears in the Geneva Bible (1560), Job 19: 20, when Job says, “I have escaped with the skin of my teeth.” Presumably, Job meant he escaped with nothing at all, because of course teeth do not have skin. By the 1600s, the expression became with or by the skin of one’s teeth and the meaning had moved away from nothing at all to its current meaning of averting something (usually disastrous) by the barest of margins. By this time, skin was commonly used as a metaphor for narrowness or thinness as in the expression, Beauty is only skin deep.