'Four' in the Bible

The leech has two daughters: "Give! Give!" There are three things that are never satisfied, four that never say, "Enough" --

There are three things that are too wonderful for me, four that I do not understand:

Under three things the earth trembles, and under four things it cannot bear up:

There are four things on earth that are small, but they are exceedingly wise:

There are three things that are magnificent in their step, four things that move about magnificently: