Shortly before the Lord Jesus Christ went to the cross his 12 disciples and some of their parents still thought that the kingdom of God was more about a physical earthly kingdom of Israel being delivered from her political enemies, such as Rome, that for people being delivered from spiritual enemies like our sinful nature and deeds, Satan and other demons or this present world system. (This earthly kingdom led by Israel and her Messiah was abundantly promised to God's chosen earthly people Israel in the Old Testament and sometimes in the New Testament but Jesus was saying the focus of His first earthly ministry was to bring in the spiritual aspect of the Kingdom of God of people whose sins are forgiven and can live in a new nature dedicated to God through His Holy Spirit and a new nature in Christ instead of the old nature focused on sin, self and Satan.) Jesus then went on to speak to his disciples and some of their parents and all of us indirectly not to seek to be like princes of the Gentiles (political, business, military, religious, entertainment etc. leaders of the nations) that are great positions in people's sight in general in this life and age but rather to be servants of God and of other people for which God would eventually give an eternal reward if it's done on the basis of faith in the Lord Jesus as our personal Lord and Saviour. Then Jesus gave an example of Himself, who fully rightly deserved to take much political authority over Israel and the world (and will after His Second Coming in glory at the end of the tribulation when He comes to rule the world from Jerusalem as King of Kings and King of Israel and Lord of the Church) for the Millennial or Messianic Kingdom then the eternal kingdom of God) but that in Jesus' first coming God had sent His only begotten Son Jesus of Nazareth to instead be a servant to the Father and in a sense to human beings to die on the cross for our sins after He lived a sinless life. In this way Jesus became a ransom for many so that all of us who admit we're sinners by nature and practice and not worthy of eternal life with God and who instead trust in or believe in Jesus as our personal Lord and Saviour who died for us on the cross and rose again can be ransomed by Jesus and have eternal blessed life with Jesus and God the Father and all His other ransomed or redeemed people of all ages physically in His presence in heaven and the Millennial and then new earth and new Jerusalem and new Heavens. We lost being God's spiritual and eternal children by default by the sin of our first parents Adam and Eve when they took of the forbidden fruit of the tree of the knowledge of good and evil that God told them not to eat of but that the devil in the serpent succeeded in tempting them to eat o in the Garden of Eden. The scripture refrence in Matthew 20 of lasting greatness for people is not in seeking to be princes and great among the nations (or pride associated with that) but humility that comes with being a servant to God and to other people with Jesus describing Himself as a good example when He went to the cross to die for our sins is as follows:
Then came to him the mother of Zebedee's children with her sons, worshipping him, and desiring a certain thing of him. And he said unto her, What wilt thou (do you want)? She saith unto him, Grant that these my two sons may sit, the one on thy right hand, and the other on thy left, in thy kingdom. But Jesus answered and said, Ye know not what ye ask. Are ye able to drink of the cup (go through the experience) that I shall drink of, and to be baptized with the baptism that I am baptized with? They say unto him, We are able. And he saith unto them, Ye shall drink indeed of my cup, and be baptized with the baptism that I am baptized with: but to sit on my right hand, and on my left, is not mine to give, but it shall be given to them for whom it is prepared of my Father. And when the ten (other disciples of Jesus) heard it, they were moved with indignation against the two brethren. But Jesus called them unto him, and said, Ye know that the princes of the Gentiles exercise dominion over them, and they that are great exercise authority upon them. But it shall not be so among you; but whosoever will be great among you, let him be your minister (servant); And whosever will be chief among you, let him be your servant; Even as the Son of man (Jesus) came not to be ministered unto (served), but to minister (serve), and to give his life a ransom for many. Gospel of Matthew 20:20-28