'Four' in the Bible

The leech has two daughters,“Give,” “Give.”There are three things that will not be satisfied,Four that will not say, “Enough”:

There are three things which are too wonderful for me,Four which I do not understand:

Under three things the earth quakes,And under four, it cannot bear up:

Four things are small on the earth,But they are exceedingly wise:

There are three things which are stately in their march,Even four which are stately when they walk: