Jesus doesn’t play around; lukewarm, middle-of-the-road neutrality will get you sent to hell. You are either for him or against him. In this passage, he is not talking about Christ-followers; we’ve already decided in favor of him; this is about people who don’t believe in anything, like atheists. He makes it clear by putting a line in the sand, figuratively speaking, and a person must stand on his side, make a decision, or their decision will be made for them. A lack of decision is a decision against Jesus.
According to the Matthew Henry Commentary, the Church of Laodicea was demolished long ago, and nothing remains but the ruins; that tells you something about how serious he is.
How boring must it be to remain neutral? We all know people in this category, and the burden is upon us to keep them in our prayers. Then if God allows us to speak to them on his behalf, the Holy Spirit will guide them into the relationship, and we will be the vessel to help. It brings great joy when he uses us as that vessel, so keep praying for your friends and family.
“‘I know your works: you are neither cold nor hot. Would that you were either cold or hot! So, because you are lukewarm, and neither hot nor cold, I will spit you out of my mouth. Revelation 3:15-16