The Laodicean church could take comfort in the fact that Christ had written a letter of rebuke to them for it was an indication of his ongoing love for them. They were not so far gone that He would leave them silently to their own devices. Like a loving Father, God chastens those who would be His sons (Deu. Deu. 8:5; 2S. 2S. 7:14; Heb. Heb. 12:5-8).
ζήλευε [zēleue] , be continually full of zeal (present-tense). The same root word as hot in Revelation Rev. 3:15+. Although God said I could wish you were cold or hot (either state being preferable to lukewarm hypocrisy), He still prefers that they be hot. The Laodicean church-goer was to earnestly desire, pursue, and strive after God.1 He could no longer remain a church-goer, but would need to become a God-chaser.
See commentary on μετανοια [metanoia] at Revelation 2:5.