This Gospel is mention in Matt.24:14 is the Gospel of the kingdom-of heaven, on earth. When God came in the flesh[Immanuel], He brought Grace, and Truth, with Him. John the Baptist preached, Repent, for the Kingdom of heaven, is at hand." The King walked among us for three and a half [3.5] years; many then and now can't see it.
Being born from above; pinch ourselves; if there is feeling, we are in time-in the flesh. This is "born of water." To be "born of the Spirit", is revelation from the Holy Spirit of YHVH.
Repentance-change of mind. Baptism-is symbolic of, death burial, and resurrection in Christ Jesus.
The Gospel of the kingdom of heaven, on earth is what we should be teaching. It is a King, and His domain. We are in the world, but not of it. Apparently many fake ones misunderstood their assignment, so they teach the "doctrine or traditions of men."
Judas was criticized for believing that Christ would restore the "kingdom of Israel", but he wasn't the only disciple to believe this. That kingdom was broken, and Tribes scattered around the world, just as stated by the Lord. The Lord has brought His Kingdom to who-so-ever-will, around the globe.
Matt.6:10 "Thy kingdom come. Thy will be done in earth, as it is in heaven." Luke 17:21 "The kingdom of God is within you." Rom.12:2 Do not conform to this world, but be ye transformed, by the renewing of your mind. John 14:2 "In My Father's house are many mansions..."; this is on the earth-right now.