Glimpses if the Gospel can be expressed in many ways to even very young children. However, as one grows one learns that the Gospel is much more beautiful than even "Jesus loves me;" as true as that statement might be.
The Gospel is the good news, announced only in the Bible that that the God who knew us and loved us before the universe existed, has chosen to give us life according to His timetable and has acted in our individual lives so as to glorify Himself via the salvation of those who are to be called His children, to repent and to believe. This God, against whom all have sinned, has willingly chosen to take upon himself the punishment that each of us deserve for those sins.
How? - Having chosen to be born as a human infant, and having lived a perfectly sinless life, He became the sinless lamb that was slain upon a cross for our sake. And, having risen from the dead, in fulfillment of the Scriptures, He became both our Lord and Savior. He died for us, so that we might live with him.
Further, Christ’s resurrection from the dead demonstrates that the wrath of God has been exhausted without any work(s) on our part. Christ’s resurrection, not our acceptance of Him, proves that the wrath of God has been exhausted against his children. For by faith we repent and believe in Jesus Christ, because God calls us to do precisely that. We cry out to him in repentance to God because He calls out to us to submit. And in doing this, we are we are (in this life) brought into a saving fellowship with Him, henceforth to rest our faith and our future glorification in Christ alone.
Note: We do not become sinless in this mortal life. Unless Christ should return we will die. But having placed our faith in Christ, the God who created us molds us into the person that He desires for us to be via the indwelling Holy Spirit. Given time we progressively grow into the likeness of the risen savior, reflecting to the world His presence in our daily life. For not only was God’s wrath poured out upon Christ for our sake but simultaneously Christ’s righteousness was poured into our lives so that we might glorify God as if neither Adam we had ever sinned.
Having been justified by the substitutionary sacrifice of our Lord and Savior Jesus Christ, we have a peace with God (in this life) that will be perfected according to His timing when we see Him. But until that time, we have been charge by our Savior to bear witness to this Gospel, to that which He has done, in the world in which we live. We are to make disciples and teach men about that which God has done, who will teach others also,
Let God be the gloried. He has accomplished that which we could not.