On a hot summer day, a cold drink is really satisfying. And on a cold winter day a hot drink is equally satisfying! However, both run into the issue of them becoming lukewarm when they’re not in an element to keep them cold or hot (such as in the refrigerator or in an insulated thermos), respectively. We don’t serve people lukewarm beverages because they just aren’t what anybody wants.
This reminds me of Revelation chapter 3. Christ revealed to John some letters that were to be sent to his churches, and one of them was telling a group of believers that they were not hot or cold, but just lukewarm. He was warning them that they were not satisfying to God. It’s easy to read this and consider it just written to the church at Laodicea, but we need to take it as a warning to ourselves, too. Just like we are not happy with a drink that is lukewarm, God is not satisfied with our relationship with him being just lukewarm. If a drink is hot or cold it is easy to tell that it is one or the other, but if it’s lukewarm it’s hard to tell whether it is supposed to be hot or cold. Similarly, it should be very clear whether or not someone has a relationship with God, there shouldn’t be any question about it.
So take this verse in Revelation as a warning. When Christ returns it should be very clear whether or not you are a follower of Jesus, and if it isn’t clear, then he says he will “spit you out of [his] mouth.” If it’s clear to you, ask someone who is around you a lot what they think? Do they clearly see that you are in a relationship with God, or do they wonder? If it’s not clear, take some time to ask God to help you. Figure out where your life is lukewarm and how you can grow in your relationship with Christ, and ask him to help you. If you’ve never asked Jesus to forgive you of your sins, start there. Ask a parent or another trusted adult if you need guidance.