I happened to think about this passage in a whole new way today because of a random, silly incident involving ice and hot water. Anyway...
In the book of Revelations 3:15-16 (ESV), Jesus tells the church in Laodicea:
For some reason, I always interpreted this passage as meaning this: if you're neither a passionate Christian (hot) nor a completely uninterested unbeliever (cold), you are lukewarm and therefore uninteresting to Jesus. I interpreted lukewarm as uninteresting!
But now, I see it differently. Whether one is hot or cold must do with the benefit one can provide to others. A follower of Christ must be a servant as Jesus was. As it follows, a Christian who is cold refreshes others through his work, and one who is hot brings warmth, perhaps sanctification. The one who is lukewarm does neither and remains totally comfortable where he is, simply serving himself.
In my previous reading of the passage, I gathered that the hearer of these words must aim to become hot (aka passionate). But, really, the way the passage reads is to serve God and people, doing good works that bless.
To come out of lukewarmness, however, entails discomfort. It's like getting out of a warm bed on a frigid winter night to get a drink for your spouse or forgoing the respite of air conditioning to play with underprivileged children at the field. To be hot or cold requires the person to endure those states. It's a command and warning to voluntarily enter into discomfort for the sake of love.
So Jesus continues to tell the church to get our of its comfort zone:
One last note: it's weird that Jesus mixes warning with wanting to dine with the hearer. What? Why mix having a meal together with service? As I can see it, there are two things to take away from this. One, a relationship with Jesus is going to require uncomfortable, sacrificial service. Two, welcoming Jesus just might mean welcoming others to share a meal at your house in order to refresh and comfort them as drawn from Matthew 10:42 (ESV):
The application could then perhaps look something like this:
Go, find a way to serve someone. A most obvious way would be to invite people to your house for a meal. There, encourage and comfort them. And in that environment of cold and hot, Jesus will dine together with those who are gathered. It's not comfortable, but it's definitely more interesting.