William Burkitt on Revelation 3:22

Thus Christ shuts up this, as he did all the preceding epistles before, with a repeated exhortation to all Christians to the end of the world, to hear, read, attend unto, and observe, all the cautions and warnings, all the reproofs and counsels, all the promises and threatenings, contained in this and the other epistles, as matters that do greatly concern all Christians to understand and know, Let him that hath an ear, hear.