Therefore, receiving a kingdom which cannot be moved, let us hold fast to the grace, by which we serve God, pleasing him with reverence and godly fear. (Hebrews 12:28)
The gospel of Mark speaks of the Son of God who will soon return and manifest an incorruptible kingdom that differs greatly from the kingdoms of men. When Jesus said that his kingdom is not of this world, some were very disillusioned. They did not understand that Jesus came to announce a very different kingdom, which he started by planting an incorruptible word (for he is the living Word of God). Over the long history of the church, many have made and are still making tragic mistakes as they attempt to take over the corrupt kingdoms of this world in the name of God.
Jesus was ordained by God and approved by God. He had no human credentials, no certificates from Herod or the Sanhedrin or the high priest, and he gave no written diplomas to his apostles. At the Last Supper, Jesus said, Verily, verily, I say unto you, He that receives whomsoever I send receives me, and he that receives me receives him that sent me (John 13:20).