Melchizedek Explanation

Apostle John who was with Christ until his last moment of the crucifixion, has revealed that Jesus Christ is not the image of Word alone, but the Image of Father, Word and the Holy Spirit, and we must believe in him to overcome this world - 5.Who is it that overcomes the world? Only the one who believes that Jesus is the Son of God. 6.This is the one who came by water and blood—Jesus Christ. He did not come by water only, but by water and blood. And it is the Spirit who testifies, because the Spirit is the truth - 1 John 5:5-6

To understand this in a better way, apostle John first explaining the Trinity of our Heavenly Father as Father, Word and Holy Spirit - because there are three who are testifying in Heaven: the Father, the Word, and the Holy Spirit, and these three are one -  1 John 5:7

And then he explained about the Son Jesus Christ, that Jesus had all three of them(Father, Son, and the Holy Spirit) in him - and there are three who are testifying in the earth: the Spirit(Holy Spirit), and the water(Word), and the blood(Father) and the three are into the one(Jesus Christ) - 1 John 5:8

That was the reason Apostle Paul is saying that Jesus Christ is the Image of the invisible God - The Son is the image of the invisible God, the firstborn over all creation - Colossians 1:15 that means in Jesus Christ we can see the Son (The Word became flesh - John 1:14), and our Heavenly Father (Whoever has seen me has seen the Father - John 14:9), and the Holy Spirit (The Spirit of the Lord is upon me - Luke 4:18).

Melchizedek's Explanation

And also at the time of Abraham, their was a world war where the team of 4 kings dominating remaining 11 nations, and In that war, Abraham's brother son Lot also taken into captive - 1.And it came to pass in the days of Amraphel king of Shinar, Arioch king of Ellasar, Chedorlaomer king of Elam, and Tidal king of nations, 2.that they made war with Bera king of Sodom, Birsha king of Gomorrah, Shinab king of Admah, Shemeber king of Zeboiim, and the king of Bela (that is, Zoar). 3.All these joined together in the Valley of Siddim (that is, the Salt Sea). 4.Twelve years they served Chedorlaomer, and in the thirteenth year they rebelled. 5.In the fourteenth year Chedorlaomer and the kings that were with him came and attacked the Rephaim in Ashteroth Karnaim, the Zuzim in Ham, the Emim in Shaveh Kiriathaim, 6.and the Horites in their mountain of Seir, as far as El Paran, which is by the wilderness. 7.Then they turned back and came to En Mishpat (that is, Kadesh), and attacked all the country of the Amalekites, and also the Amorites who dwelt in Hazezon Tamar. 8.And the king of Sodom, the king of Gomorrah, the king of Admah, the king of Zeboiim, and the king of Bela (that is, Zoar) went out and joined together in battle in the Valley of Siddim 9.against Chedorlaomer king of Elam, Tidal king of nations, Amraphel king of Shinar, and Arioch king of Ellasar—four kings against five. 10.Now the Valley of Siddim was full of asphalt pits; and the kings of Sodom and Gomorrah fled; some fell there, and the remainder fled to the mountains. 11.Then they took all the goods of Sodom and Gomorrah, and all their provisions, and went their way. 12.They also took Lot, Abram’s brother’s son who dwelt in Sodom, and his goods, and departed - Genesis 14:1-12

And Bible says that Abraham defeated the 4 kings with 318 of his servants and three men Mamre, Eshcol and Aner, and finally Abraham gave tithe to Melchizedek - 13.Then one who had escaped came and told Abram the Hebrew, for he dwelt by the terebinth trees of Mamre the Amorite, brother of Eshcol and brother of Aner; and they were allies with Abram. 14.Now when Abram heard that his brother was taken captive, he armed his three hundred and eighteen trained servants who were born in his own house, and went in pursuit as far as Dan. 15.He divided his forces against them by night, and he and his servants attacked them and pursued them as far as Hobah, which is north of Damascus. 16.So he brought back all the goods, and also brought back his brother Lot and his goods, as well as the women and the people. 17.And the king of Sodom went out to meet him at the Valley of Shaveh (that is, the King’s Valley), after his return from the defeat of Chedorlaomer and the kings who were with him. 18.Then Melchizedek king of Salem brought out bread and wine; he was the priest of God Most High. 19.And he blessed him and said: “Blessed be Abram of God Most High, Possessor of heaven and earth; 20.And blessed be God Most High, Who has delivered your enemies into your hand.” And he gave him a tithe of all. 21.Now the king of Sodom said to Abram, “Give me the persons, and take the goods for yourself.” 22.But Abram said to the king of Sodom, “I have raised my hand to the Lord, God Most High, the Possessor of heaven and earth, 23.that I will take nothing, from a thread to a sandal strap, and that I will not take anything that is yours, lest you should say, ‘I have made Abram rich’, 24.except only what the young men have eaten, and the portion of the men who went with me: Aner, Eshcol, and Mamre; let them take their portion.” - Genesis 14:11-24

Though the Tithe was given to the single man Melchizedek, the portion was shared with three men Mamre, Eshcol and Aner, like this prophecy Jesus Christ is the image Father, Word and the Holy Spirit.