If any man have an ear, let him hear - See the notes on Revelation 2:7. The idea here is, that what was here said respecting the "beast" was worthy of special attention, as it pertained to most important events in the history of the church.

If any man have an ear, let him hear - These words are evidently introduced to impress the reader with the awfulness of what has just been spoken - all shall worship him whose names are not written in the book of life, as well as to fix his attention upon the following words: -

(14) If any man have an ear, let him hear.
(14) The conclusion of this speech of the first beast, consisting of two parts, an exhortation to attentive audience, in this verse: and a foretelling, which partly contains threatenings against the wicked and partly comfort for those who in patience and faith shall wait for that glorious coming of our Lord and Saviour Christ; (Revelation 13:10)

If any man have an ear, let him hear. And diligently attend to this mystical description of antichrist, as being matter of some difficulty to understand, as well as of great moment and importance, and seriously consider it, that he may know him, and his followers, and avoid them; See Gill on Revelation 1:7.

A general exhortation. Christ's own words of monition calling solemn attention.