We are familiar with the Seven Churches as found in Revelation 2 and 3; however I’d like to look into why each church was either alive or dead, and what can be learned about each one.

Now a church is a group of people attending together worshiping God, so the churches themselves fall into these groups when the members themselves do the same.

Third warning: The danger of becoming lukewarm

This warning comes from the church of Laodicea in Revelation 3: 15-17

 “I know your works, that you are neither cold nor hot. I could wish you were cold or hot.  So then, because you are lukewarm, and neither [k]cold nor hot, I will vomit you out of My mouth. Because you say, ‘I am rich, have become wealthy, and have need of nothing’—and do not know that you are wretched, miserable, poor, blind, and naked

So how can one become a lukewarm Christian? There are many ways, but in the interest of space [and time] we'll go over a few. One is by being faithful when convenient or out of some selfish desire to see what can be gained from worship.

2 Corinthians 13: 5

Examine yourselves as to whether you are in the faith. Test yourselves. Do you not know yourselves, that Jesus Christ is in you?—unless indeed you are disqualified.

We all must examine ourselves regularly. Are we in the faith? Is our worship acceptable to God? Do we even care? 

We usually hear to examine ourselves during the Lord's supper, but it's something that must be done through the entire service.

We also can be lukewarm by looking at our past and resting on our laurels. It's so easy to do. "I've preached many times, I teach bible classes, I've lead so many to Christ..." but the life of a Christian is one of continual growth. 

Or, as Paul says in Colossians 1: 9-12

For this reason we also, since the day we heard it, do not cease to pray for you, and to ask that you may be filled with the knowledge of His will in all wisdom and spiritual understanding; that you may walk worthy of the Lord, fully pleasing Him, being fruitful in every good work and increasing in the knowledge of God; strengthened with all might, according to His glorious power, for all patience and longsuffering with joy;  giving thanks to the Father who has qualified us to be partakers of the inheritance of the saints in the light.

This is all present tense. Even in a church that has done as much good as they have must continue walking worthily, being fruitful, and increasing in knowledge.

So look at your life today. Are you growing as a Christian? Are you walking worthily? Is your worship to God as it should be?  Only I can answer that question for myself, only you can for yourself.