I believe that the purest answer lies within what the word "euangelion" meant to the original, First Century hearers. It was a widely used term which had no religious connotations at the time, and was understood as the heralding of one of three things: The Birth of a King, The Triumph of a King over his enemies, and a Regime Change (New King/New Order).
Hence, when the early church used the word "Euangelion"/Gospel, it was understood that a new King had been born, that He had defeated His enemies, and that there was indeed a regime change when Jesus was officially coronated through the finished work of the cross. Making those claims about Jesus was a revolutionary declaration that "Jesus is King" (and Caesar is not).
It meant so much more than today's typical "Evangelical" message. While there are many components of "The Gospel", I believe that what I have described is the crux of the Gospel. Just as "Hail to the Chief" is used to herald a U.S. President, "Euangelion" was a word reserved specifically for the ruling Caesar (or his successor) of that day.
Peace & Love!
There are Rabbis and Imams who sound like mad men. There are also many of them who sound more like Jesus than a good number of their professing, Christian counterparts; especially on matters pertaining to peaceful, loving coexistence.
I Love Jesus, The Prince of Peace, and believe with all of my heart that He is The Way, The Truth, The Life, The Resurrection, The Brightness of the Father's Glory, and the Express Image of His Person. My problem is not with Him, it's with the preachers and politicians who have knowingly or unwittingly misrepresented Him as a warmongering, real estate tycoon Who is bent on the ethnic cleansing of "bad people" in order for the "chosen people" to get what is rightfully theirs.
Too many people have taken on the role of judge, jury, and executioner (or simply supported it through proxy nations), instead of following the Beatitudes. Others are so ignorantly bent on historical, First Century calamities being unleashed (a second time...which has no solid, Biblical or historical foundation) in their lifetime, that they actually long for war and the destruction of "the bad people".
The sad irony is that The Great Commission has everything to do with bringing LIFE and nothing to do with God's "chosen people" being purveyors of ethnic cleansing and destruction.
We have been called to be Peace Makers, not Crusaders!
Peace, Salam, & Shalom!
Theology matters. It shapes our worldview and our worldview shapes how we treat people and creation in general.
There are plenty of folks who will tell you that they're "not into Theology". Many of those same folks will also be quick to tell you "What the Bible clearly says". Whether you are an avid student of the Bible or someone who has checked all of your denomination's "What We Believe" boxes, you have a theology.
For the most part, our worldview is either based upon personal study, with the Holy Spirit as our primary Teacher, or we receive it by defaulting to someone else's prescribed settings.
Theology is best forged through a life-long, personal relationship with Jesus Christ and the Body of Christ, as He Lives His Life through His people who are one with The Word and Words within the Word (The Logos/Logic of God).
Lo, in the volume of the Book it is written of us, to do Your Will O God!
Peace & Love!