I am looking to the Apostle Paul and his zeal and his love of preaching the Gospel and exactly what the Gospel is that he preached. When he was ready to go to Jerusalem, not knowing what would befall him there, he said this to those who were gathered:

“But none of these things move me, neither count I my life dear unto myself, so that I might finish my course with joy, and the ministry, which I have received of the Lord Jesus, to testify the Gospel of the Grace of God” (Acts 20:24)

There is much controversy over what specific truths of the scripture make up the Gospel, but one thing we know without wavering, without hesitation is that it is by GRACE and grace alone. Paul taught grace and he taught it without apology, because Jesus Christ had taught it to him, we can believe it and proclaim it the same, without apology! Understanding grace then is of utmost importance as through that knowledge He directs us most assuredly to all the truths that make up the Gospel of the Grace of God. 
 

"For by grace ye have been saved through faith; and that not of yourselves: it is the gift of God: not of works, lets any man should boast" (Ephesians 2: 8, 9)

There are countless scriptures that tell us that ALL of salvation is ALL of grace; the one above quoted from Ephesians is a clear statement of that very thing, the glorious truth of grace alone, no works, no boasting!

What is grace then? I try and keep things as simple as possible and I believe that we can do that with grace, although the actual reality of God’s grace for believer’s still knocks us to the ground in total awe and the wonder of it. Grace has been eloquently stated as unmerited favor, so it is the favor of God upon a total undeserving person. Grace is solely a work of God despite what we are or what we have done or what we will do. Grace is all of God and we have no part in it, none and that is usually where men like to depart from the Gospel so for me it is vitally important to always keep in mind that the work of God in the salvation of His people is all of grace and is specifically what the Gospel is about, that very grace.

Ephesians 2: 8 & 9 tells us then that our salvation is by grace, it is through faith and that the grace and the faith are not our own, they are the gifts of God and only His to give. It isn’t of men’s works either so from this scripture alone we can know the Gospel boundary; it has to be of Grace. If it is not of Grace and leaves room for men to contribute, in any way, to their own salvation it is not the Gospel of the Grace of God, it is another Gospel. So we can search the scriptures and we can know what we are given this gift of faith to believe for the scriptures tell us that 'we have heard the word of the truth in the gospel' (Colossians 1:5) and they tell us that we are to stand fast because “……God hath from the beginning chosen you to salvation through sanctification (being set apart unto Him) by the Spirit and belief of the truth: Whereunto he called you by our Gospel….” (2 Thessalonians 2: 13, 14). So it is by the faith that we are given that we believe the truth and we make that same confession with our mouth. (Romans 10:10)