There are several verses that are translated in our English Bibles to imply that insects have four legs. In reality, the Hebrew word sherets, translated as "insect" is not nearly as specific as the term "insect" would imply. The word really refers to crawling or swimming creatures that tend to swarm together. For example, in Genesis, sherets refers to swarming sea creatures,27 in the flood account (Genesis 7) sherets refers to rodents,28 and in Leviticus, sherets refers to crustaceans,29 insects,30 rodents,31 and reptiles.32 The term sherets was never intended as a biological classification system, so to say that it specifically refers to "insects" is deceptive.
What is common among all the creatures mentioned is that they have short legs and often travel together in groups. In fact, the Bible defines sherets as "crawling on its belly" and "whatever walks on all fours."33 What is common in this group of crustaceans, insects, rodents, and reptiles is that they all crawl on "all four" legs. Some from this group actually have more than four legs. However, the Hebrew idiom "on all fours" refers to any creature that crawls low to the ground on at least four legs. Were the writers of the Bible unaware that insects have six legs? This statement would seem rather silly, but atheists actually make this claim. However, one of the verses clearly indicates that these "four-legged" insects have six legs:
'Yet these you may eat among all the winged insects [sherets] which walk on all fours: those which have above their feet jointed legs with which to jump on the earth. (Leviticus 11:21)