Is the gospel justification by grace through faith?
The gospel IS salvation from God's wrath against sin, by grace through Spirit-wrought faith in the finished work of Jesus' perfect life, his substitutionary and atoning death upon the cross, and his victorious resurrection from among the dead. But, the gospel IS NOT limited to justification by grace through faith in Jesus. (Justification may very well be the decisive and principle action whereby we experience the benefits of the gospel, but it is not by itself the good news of the kingdom.)
To understand the good news of Jesus rightly one must first understand what bad news the good news of his kingdom purports to correct.
What is the bad news?
The bad news IS that, in Adam, we are enslaved to disobedience, we are a fallen people, utterly incapable of rightly imaging God and obeying his moral law; and because of that improper imaging and failure to keep his commands, the warrant of eternal death looms grimly over all humanity. But, the bad news IS NOT limited to damnation for sin.
To understand the bad news rightly one must go back to that moment in history when the first law was broken, when sin entered the world through Adam. What was lost in that first seditious act? The answer to that question is the bad news that the good news of Jesus corrects. Expulsion from paradise; separation from God, from the Tree of Life, from shalom, perfect health, safety, purpose, work without toil, ease in childbearing, and relational and marital harmony. That is the bad news. The bad news of death through sin is, of course, part of the curse through sin, but it is not the sum total of the bad news.
If that is true, that the bad news is not limited to salvation from death through sin, then the good news cannot be limited to eternal life by grace through faith in Jesus Christ. It is certainly not less than eternal life, but it cannot be limited to eternal life alone. Eternal life with God is good news, to be sure, but the gospel of Jesus and his kingdom is much bigger news than mere forever-life after death.
This is the Good News!
The gospel IS the good news that Jesus is King and his kingdom is come — and is yet to come; that he's the long awaited serpent's-head-crushing-bruised-heel seed of the woman and seed of Abraham, through whom all the world is now blessed and the curse is broken; that he’s disarmed the cherubim guarding the Garden's gate, that we may eat freely from the Tree of Life; that he’s soon coming to purge the Land and eject all wickedness, evildoers, Satan, sin, death, and Hell into eternal perdition; that he's going to recreate the heavens and the earth into an edenic heavenly city flowing with milk and honey, where there is no need of the sun because Jesus is our light; that he’s reconciled us to our Father, restored shalom, perfect health, safety, purpose, work without toil, and relational harmony among his people; that the lamb will lie down with the wolf, that weapons of war will be beaten into plowshares, that the last will be first, that the marginalized will be brought to the center, that the downtrodden and outcast are invited to feast at the table of our great King; that he's given us a new forever family in the church; and, that he's given us a mission of delighting in him to such a degree that our hearts overflow our lips and we proclaim the good news of Jesus and his kingdom come, with our hands and feet following suit.
The gospel is the good news that we are justified by grace through faith in Jesus. However, the gospel is also the good news that through King Jesus, by King Jesus, and because of King Jesus, everything that was lost by Adam through sin is now suddenly all becoming untrue!
You're not just being saved from wrath, Beloved, you've also been saved into a family and unto the mission of covering the earth with the knowledge of God by discipling the nations!
"This gospel of the kingdom shall be preached in the whole world as a testimony to all the nations..." Matt 24:14