Here is what Piper says:
Here is a simple exhortation that I have been trying to implement in our family:
Seek to see and feel the gospel as bigger as years go by rather than smaller.
Our temptation is to think that the gospel is for beginners and then we go on to greater things. But the real challenge is to see the gospel as the greatest thing—and getting greater all the time.
The Gospel gets bigger when, in your heart,
- grace gets bigger;
- Christ gets greater;
- his death gets more wonderful;
- his resurrection gets more astonishing;
- the work of the Spirit gets mightier;
- the power of the gospel gets more pervasive;
- its global extent gets wider;
- your own sin gets uglier;
- the devil gets more evil;
- the gospel's roots in eternity go deeper;
- its connections with everything in the Bible and in the world get stronger;
- and the magnitude of its celebration in eternity gets louder.
So keep this in mind: Never let the gospel get smaller in your heart.
Pray that it won't. Read solid books on it. Sing about it. Tell someone about it who is ignorant or unsure about it.
Now I would remind you, brothers, of the gospel.... For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures. (1 Corinthians 15:1-4)