What is the gospel?

A few weeks ago I attended a meeting of the Central Arkansas Theological Society (C.A.T.S.). Although it sounds fancy, it is just a group of guys (mostly from Redeemer LR) who get together, listen to a talk, and then discuss it.

We listened to Tim Keller talk about The Reason for God which was part of the Authors@Google series. I enjoyed the talk. Keller was winsome and engaged his audience appropriately. It had a Paul-in-Athens (Acts 17) feel.

However since I had already read a fair amount of his book and listened to the talk, I was more interested in the ensuing discussion. Our discussion centered mostly around a few objections that Keller did not make a clear presentation of the gospel. These reason's were offered in defense of Keller:

1. He was being sensitive to his context (i.e. he needed to build trust and credibility with his audience - a crowd of cynics and skeptics). Thumping his Bible (so to speak) would have been counter productive.

2. He was tilling the soil of their hearts (1 Corinthians 3:5-6 was cited).

3. He was asked to come to speak on a specific subject (the kind of reasoning that leads to monotheism - not Christianity necessarily). Straying from that subject too much would have been disrespectful and displayed a lack of integrity.

4. He did share the gospel (e.g. 39:50 - 41:48)

I agreed with all these sentiments, but reason #4 was the most compelling. Interestingly, it also exposed the hidden assumption that we all had the same definition of the gospel. Here's the essence of what Keller said about the gospel:

1. God created the world.

2. God created man.

3. God fell in love with man.

4. God saw man was suffering.

5. God entered the world to save man.

Clearly, some felt that was adequate and some didn't. My question isn't so much about the merits of what Tim presented, but about the gospel in general.

What is the pure essence of the gospel without which it can no longer be called the gospel?

We know from Galatians 1:8-9 that there is a true gospel and a false gospel. Getting the gospel fundamentally wrong will have eternal consequences so we would do well to get it as right as possible to the finest detail.

For further stimulation on this topic I suggest Trevin Wax's "The Gospel of God: Personal Atonement or Christ's Kingdom?" and his fascinating series on Gospel Definitions. I also found Scot McKnight's "Is Our Gospel Too Small" interesting.

Personally, I lean toward definitions of the gospel which are very concise but have broad implications (e.g. "Jesus is Lord") which are then made truly understandable by patient explanation and personal demonstration (i.e. self-sacrificing love).

What do you think? I would love to see a whole C.A.T.S. meeting devoted to this topic.