In the Old Testament, kings, priests, and prophets were anointed and established. So the word Christ means king, prophet, and priest. To say that Jesus is the Christ means that Jesus is the true King, the true Priest, and the true Prophet. The Anointed One is the Hebrew word for ישו(Messiah). (Psalm 2:2) The Greek word for Messiah is Χριστός ( Christos). In English, it is ‘Christ’.
Ps 2:2 The kings of the earth set themselves, and the rulers take counsel together, against the Lord, and against his anointed, saying,
Let’s see why we need Christ.
Jesus the True King Our ancestor Adam was deceived by Satan and ate of the forbidden fruit, and as a result, we became Satan’s servants. (Jn 8:44) Jn 8:44 Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.
But God promised to send Christ to Adam to save us. (Gen 3:15)
Gen 3:15 And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
Christ has come to this earth. That Jesus is the Christ. That is, Jesus fulfilled the work of the true King, true Priest, and true Prophet. Jesus did the work of the true King, destroying the works of Satan. (1 Jn 3:8)
1 Jn 3:8 He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.
Jesus the True Priest Because of Adam’s sin, all people are born sinners. (Rom 3:23)
Rom 3:23 For all have sinned, and come short of the glory of God;
Jesus became the ransom to forgive our sins. That is, He did the work of the true Priest. (Mk 10:45)
Mk 10:45 For even the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.
Jesus the True Prophet Also, we were unable to meet God because of our sins. (Isa 59:2)
Isa 59:2 But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear.
Jesus opened the way to meet God by dying for our sins. In other words, He did the work of the true Prophet. (Jn 14:6)
Jn 14:6 Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
Jesus completed the work of Christ (true King, true Priest, true Prophet) by dying on the cross. (Jn 19:30)
Jn 19:30 When Jesus therefore had received the vinegar, he said, It is finished: and he bowed his head, and gave up the ghost.
So Jesus is the Christ.