What is one way the Gospel can be summed up?

Rob Ventura explains in this video that when we speak about Christ as our substitute, that is the heart of the Gospel. 

A substitute is one who stands in place of another. Jesus is our substitute, He took our sins upon Himself. In short, the Gospel can be summed up by the word "substitute." Christ was our perfect, sin-atoning sacrifice. 

Ephesians 2:8-9 (NKJV) - "For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast."

So when we speak about Christ as substitute, we should be very clear, I think, that as Spurgeon said, the word substitution is really the heart of the gospel. In my place condemned he stood, as the hymn writer said, sealed my pardon with his blood, hallelujah what a Savior. So when I asked the children at the church what is a substitute, it's one who stands in the place for another. I say if your teacher is out sick you have what a substitute. Jesus is the substitute.

He's the one who stood in our place and took our sins upon himself and was punished on our behalf. So, substitution is really the glory of the gospel. If you had to sum it up, What's the gospel about? It's about Christ willingly in love, substituting Himself to be our sin-atoning sacrifice. You