Matthew 8:1-4 (ESV)
1 When he came down from the mountain, great crowds followed him.
2 And behold, a leper came to him and knelt before him, saying, “Lord, if you will, you can make me clean.”
3 And Jesus stretched out his hand and touched him, saying, “I will; be clean.” And immediately his leprosy was cleansed.
4 And Jesus said to him, “See that you say nothing to anyone, but go, show yourself to the priest and offer the gift that Moses commanded, for a proof to them.”
Why does Jesus send the man to the Priest? To fulfill the Law of Moses.
Leviticus 14:2 ff (ESV) “This shall be the law of the leprous person for the day of his cleansing. He shall be brought to the priest,
Leviticus 14:7 (ESV) … Then he shall pronounce him clean ….
Was not Jesus fully capable of declaring the man clean? I mean He healed him. He has cleansed all of His own.
John 13:6-11 (ESV)
6 He came to Simon Peter, who said to him, “Lord, do you wash my feet?”
7 Jesus answered him, “What I am doing you do not understand now, but afterward you will understand.”
8 Peter said to him, “You shall never wash my feet.” Jesus answered him, “If I do not wash you, you have no share with me.”
9 Simon Peter said to him, “Lord, not my feet only but also my hands and my head!”
10 Jesus said to him, “The one who has bathed does not need to wash, except for his feet, but is completely clean. And you are clean, but not every one of you.”
11 For he knew who was to betray him; that was why he said, “Not all of you are clean.”
1 Corinthians 6:11 (ESV) And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God.
Ephesians 5:25-27 (ESV)
25 Husbands, love your wives, as Christ loved the church and gave himself up for her,
26 that he might sanctify her, having cleansed her by the washing of water with the word,
27 so that he might present the church to himself in splendor, without spot or wrinkle or any such thing, that she might be holy and without blemish.
Titus 3:4-7 (ESV)
4 But when the goodness and loving kindness of God our Savior appeared,
5 he saved us, not because of works done by us in righteousness, but according to his own mercy, by the washing of regeneration and renewal of the Holy Spirit,
6 whom he poured out on us richly through Jesus Christ our Savior,
7 so that being justified by his grace we might become heirs according to the hope of eternal life.
Hebrews 10:21-22 (ESV)
21 and since we have a great priest over the house of God,
22 let us draw near with a true heart in full assurance of faith, with our hearts sprinkled clean from an evil conscience and our bodies washed with pure water.
Was not Jesus fully a Priest?
Hebrews 4:15 (ESV) For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin.
Hebrews 7:25-26 (ESV)
25 Consequently, he is able to save to the uttermost those who draw near to God through him, since he always lives to make intercession for them.
26 For it was indeed fitting that we should have such a high priest, holy, innocent, unstained, separated from sinners, and exalted above the heavens.
The Law of Moses was still in effect because Jesus had not yet fulfilled the Law (Matthew 5:17) nor accomplished all (Matthew 5:18).
Jesus cleansed the Leper and followed all the Law of Moses. Just as He told John the Baptist about His baptism He suffered it to be so for now.
Matthew 3:15 (KJV) And Jesus answering said unto him, Suffer it to be so now: for thus it becometh us to fulfil all righteousness.