Matthew 17:
1After six days Jesus took with him Peter, James and John the brother of James, and led them up a high mountain by themselves.
2There he was transfigured before them. His face shone like the sun, and his clothes became as white as the light.
3Just then there appeared before them Moses and Elijah, talking with Jesus.
4Peter said to Jesus, "Lord, it is good for us to be here. If you wish, I will put up three shelters—one for you, one for Moses and one for Elijah."
5While he was still speaking, a bright cloud enveloped them, and a voice from the cloud said, "This is my Son, whom I love; with him I am well pleased. Listen to him!"
6When the disciples heard this, they fell facedown to the ground, terrified.
7But Jesus came and touched them. "Get up," he said. "Don't be afraid."
8When they looked up, they saw no one except Jesus.
9As they were coming down the mountain, Jesus instructed them, "Don't tell anyone what you have seen, until the Son of Man has been raised from the dead."

I always wondered what this meaning was? The name Peter means rock, on which the law was written in Moses time, the name James means replacement or substitute, the name John means God's grace.
So the law was replaced or substituted by God's grace!
Peter, spoke saying I will put up three shelters; one for Moses, the law, which would be replaced by grace (for now we are no longer under the law but under grace),
one for Elijah (John the Baptist whose water baptism would be replaced by Jesus (John the Baptist whom Jesus referred to as Elijah baptized with water; John answered them all, "I baptize you with water. But one more powerful than I will come, the thongs of whose sandals I am not worthy to untie. He will baptize you with the Holy Spirit and with fire.))
and one for JESUS who is the grace of God. God the FATHER said; This is my Son, whom I love; with him I am well pleased. Listen to him!" (When they looked up, they saw no one except JESUS.)(His face shone like the sun, and his clothes became as white as the light)(we are made clean and washed by the blood, whiter than snow, we become the light that shines in the darkness, we are transfigured like JESUS))
The law,(Moses)and the prophet,(Elijah)disappears, only Jesus who is grace remains, By his resurrection, he is the one who remains! The law and the prophets that could not save us were replaced by the Son, JESUS, who is always with us, that God the FATHER said; This is my Son, whom I love; with him I am well pleased. Listen to him!" Jesus knew that this would have fulfilled meaning when Jesus instructed them, "Don't tell anyone what you have seen, until the Son of Man has been raised from the dead." Why? Because then grace reigns, the love and mercy of God the FATHER and JESUS the son of the FATHER, is completed for us, we are no longer under the law nor need to live by the law to be saved, we are not only washed by water only to become unclean again but we are saved by the resurrection of Jesus who is always with us, and saved by grace because of the mercy and love he has for us by taking our punishment upon himself, so we are clean and righteous forevermore. (baptized with the HOLY SPIRIT and with fire) So we look to no man, but to the SON OF GOD only, JESUS, listen to him only.

Jesus said "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them". Then, what does this mean? It means that when we become born again of the spirit of God, when we become new spirit creatures, we are given the HOLY SPIRIT as a guide and counselor during our lifelong sanctification process, JESUS lives in us as the power to overcome sin, we crucify the flesh daily that we might live by the spirit which gives us life, and frees us from sin. the law shows us our sin, the grace and mercy of JESUS when we believe in him gives us the power to overcome it.

Acts 16:31 "Believe in the Lord JESUS, and you will be saved",
Once we believe, we are born again, once we are born again and justified (we are made righteous in God's eyes by the blood of JESUS shed for us and our sins), we then begin the lifelong process of sanctification, we become more and more like JESUS because he lives in us, his HOLY SPIRIT guides us, and we overcome sin by his power in us. We do not overcome sin by our own power, but by his power alone! So we look to no man, but to the SON OF GOD only, JESUS, listen to him only.