Commentary On Revelation 3:15

The deeds of the Laodicean Christians manifested their heart attitude. They were neither cold nor hot in their love for God, just lukewarm. Beverages are better either cold or hot. Similarly the Lord would rather that His people be cold or hot in their love for Him, not apathetic. The Laodiceans knew how the Lord felt because their city drinking water came from a spring six miles to the south over an aqueduct, and it arrived disgustingly lukewarm. [Note: Beasley-Murray, p105.]

"Neighboring Hierapolis had hot, spring water, valuable for its medicinal effects. In its journey to Laodicea it lost some of this heat and consequently medicinal value by the time it arrived either overland or by aqueduct in Laodicea. Nearby Colosse had cool, life-giving water that was refreshing as a beverage (Hemer)." [Note: Thomas, Revelation 1-7 , p307. Cf. M. J. S. Rudwick and E. M. B. Green, "The Laodicean Lukewarmness," Expository Times69 (1957-8):176-78; and Hemer, pp432-40.]

The Lord's spitting (lit. vomiting) His people out of His mouth (Revelation 3:16) does not mean they would lose their salvation...This anthropomorphism simply indicates His intense disgust. He did not mean that He would rather we be spiritually cold than that we be spiritually lukewarm either. He did mean that He would rather we be spiritually refreshing or healthful, as cold or hot water, rather than that we be spiritually bland, as lukewarm water. This explanation seems more likely than the one that identifies the Laodiceans as unbelievers.

The Laodiceans enjoyed material prosperity ( Revelation 3:17) that led them to a false sense of security and independence. The expression "I am rich, and have become wealthy" is a literary device that inverts the natural sequence for emphasis (cf. Revelation 3:19; Revelation 5:2; Revelation 5:5; Revelation 10:4; Revelation 10:9; Revelation 12:10; Revelation 19:13). Here it stresses that the wealth attained came though self-exertion. Spiritually they had great needs (cf. Romans 7:24). This self-sufficient attitude is a constant danger when Christians live lives of ease and enjoy plenty.

Constable, Thomas. DD. "Commentary on Revelation 3:4". "Expository Notes of Dr. Thomas Constable". https://www.studylight.org/commentaries/dcc/revelation-3.html. 2012.