Matthew 4.17 From that time, Jesus began to preach, and to say, “Repent! For the Kingdom of Heaven is at hand.”
This is one of the most fundamental messages that Christ brought to the world. Jesus appeared during a time of Roman occupation in Israel, a time that many felt oppressed and abused by the system of rule that was in place. There had been a time in Israel's history, when King David and King Solomon ruled, when Israel had been a sovereign nation, not controlled by any foreign power. But those days were long gone. Now Jesus brings a message that there is a greater power, a greater rule in operation, a greater kingdom operating in the present time, that being the Kingdom of Heaven.
In light of this truth, that God himself is the ultimate dispenser of justice and the ultimate sovereign determining the fate of each individual and of whole nations, we should turn away from unrighteous behavior, and seek to serve the Kingdom of Heaven, living under the laws of God's kingdom, without unholy fear of any earthly kingdom.
Matthew 28.18 Jesus came to them and spoke to them, saying, “All authority has been given to me in heaven and on earth.19 Go, and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 teaching them to obey everything that I commanded you. Behold, I am with you always, even to the end of the age.” Amen.
This famous passage is known as the Great Commission, spoken by Jesus just before he was taken up into heaven following his resurrection from the dead. It was one of his last commands to his disciples, and it captured the assignment he gave to them as to how they were to continue to carry out the ministry of Christ after he departed for heaven.
It is therefore incumbent upon us as those who seek to follow Christ to obey him, and to obey everything he commanded his disciples. We must pay attention to what Jesus taught his disciples to do, both implicitly and explicitly, and seek not only to do it, but to teach others to do it as well.