The sole purpose of the comma is the unfolding of the sense of the words.
III.

The comma cannot be correctly used without a thorough understanding of the sense of the words.
IV.

In case of doubt, omit the comma.
THE SEMICOLON The semicolon is used to denote a degree of separation greater than that indicated by the comma, but less than that indicated by the colon.

It prevents the repetition of the comma and keeps apart the more important members of the sentence.

The semicolon is generally used in long sentences, but may sometimes be properly used in short ones.
_Rules for the Use of the Semicolon_ 1.