“Now after John was arrested, Jesus came into Galilee, proclaiming the gospel of God, and saying, “The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel.” Mark 1:14-15
These words are all about Jesus, who He is and what He is doing.
“The time is fulfilled” – Not a time of day but the fulfillment of time; a specific moment of fulfillment. The long awaited Messiah is here and in action!
“The kingdom of God is at hand” – Jesus is where we find God’s kingdom. He is here! Near to them; at hand! His kingdom of grace, mercy, peace and joy (and much more) wrapped up in Him and Him alone.
“Repent and believe the gospel (good news)” – turn our focus off ourselves and the false gods we live for and onto Jesus and His gospel message. His good news is, again, found in Him and Him alone. Jesus is the gospel of God, in the flesh.