Out Of My Mouth -Revelation 3:16

Revelation 3:16 ESV
So, because you are lukewarm, and neither hot nor cold, I will spit you out of my mouth.

Being lukewarm implies comfort, body temperature.
Being comfortable in our flesh is not where we need to be. If we are cold we are more likely to seek the warmth of His Spirit. If we have the Spirit and walk in His way, we find ourselves hot in the embers of His refining fire. Hot or cold, we are in motion, moving in some direction. If we are lukewarm we are stagnant and become as the water in the dead sea.
His patience will not last forever.

Spit -emeō * em-eh'-o * Of uncertain affinity; to vomit: - (will) spue. [LEX] [TGD] [Find] ] thee out of my mouth. (CWS)
An unpleasant taste to be expelled.

Mouth. στόμα * stoma * stom'-a * Probably stregthened from a presumed derivative of the base of G5114; the mouth (as if a gash in the face); by implication language (and its relations); figuratively an opening (in the earth); specifically the front or edge (of a weapon): - edge, face, mouth. (CWS)
No longer will they be a people of His word once vomited from His mouth. His word will judge.


Jeremiah 15:1-3
1 Then the Lord said to me, “Though Moses and Samuel stood before me, yet my heart would not turn toward this people. Send them out of my sight, and let them go! 2 And when they ask you, ‘Where shall we go? ’ you shall say to them, ‘Thus says the Lord:
“‘Those who are for pestilence, to pestilence,
and those who are for the sword, to the sword;
those who are for famine, to famine,
and those who are for captivity, to captivity. ’
3 I will appoint over them four kinds of destroyers, declares the Lord: the sword to kill, the dogs to tear, and the birds of the air and the beasts of the earth to devour and destroy.

Zechariah 11:8-10
In one month I destroyed the three shepherds. But I became impatient with them, and they also detested me. 9 So I said, “I will not be your shepherd. What is to die, let it die. What is to be destroyed, let it be destroyed. And let those who are left devour the flesh of one another.” 10 And I took my staff Favor, and I broke it, annulling the covenant that I had made with all the peoples.