So then because thou art lukewarm I will spue thee out of my mouth - Referring, perhaps, to the well-known fact that tepid water tends to produce sickness at the stomach, and an inclination to vomit. The image is intensely strong, and denotes deep disgust and loathing at the indifference which prevailed in the church at Laodicea. The idea is, that they would be utterly rejected and cast off as a church - a threatening of which there has been an abundant fulfillment in subsequent times. It may be remarked, also, that what was threatened to that church may be expected to occur to all churches, if they are in the same condition; and that all professing Christians, and Christian churches, that are lukewarm, have special reason to dread the indignation of the Saviour.

Because thou art lukewarm - Irresolute and undecided.
I will spue thee out of my mouth - He alludes here to the known effect of tepid water upon the stomach; it generally produces a nausea. I wilt cast thee off. Thou shalt have no interest in me. Though thou hast been near to my heart, yet now I must pluck thee thence, because slothful, careless, and indolent; thou art not in earnest for thy soul.

So then because thou art lukewarm, and neither cold nor hot,.... A lukewarm professor is one that serves God and mammon; that halts between two opinions, and knows not what religion is best, and cares little for any, yet keeps in a round of duty, though indifferent to it, and contents himself with it; and is un concerned about the life and power of godliness, and takes up with the external form of it; and has no thought about the glory of God, the interest of Christ and truth; and this was too much the case of this church, at least of a great number of its members; wherefore it was very loathsome to Christ, hence he threatens:
I will spew thee out of my mouth; this shows how nauseous lukewarmness is to Christ, insomuch that on account of it he would not own and acknowledge her as his; but even cast her out, unchurch her, and have no more any such imperfect church state upon earth, as he afterwards never will, this is the last; nor is there any church state, or any remains of one in Laodicea; it is indeed quite uninhabited.

neither cold nor hot--So one oldest manuscript, B, and Vulgate read. But two oldest manuscripts, Syriac, and Coptic transpose thus, "hot nor cold." It is remarkable that the Greek adjectives are in the masculine, agreeing with the angel, not feminine, agreeing with the Church. The Lord addresses the angel as the embodiment and representative of the Church. The chief minister is answerable for his flock if he have not faithfully warned the members of it.
I will--Greek, "I am about to," "I am ready to": I have it in my mind: implying graciously the possibility of the threat not being executed, if only they repent at once. His dealings towards them will depend on theirs towards Him.
spue thee out of my month--reject with righteous loathing, as Canaan spued out its inhabitants for their abominations. Physicians used lukewarm water to cause vomiting. Cold and hot drinks were common at feasts, but never lukewarm. There were hot and cold springs near Laodicea.

So because thou art lukewarm - The effect of lukewarm water is well known. I am about to spue thee out of my mouth - I will utterly cast thee from me; that is, unless thou repent.