King David says of his Messiah in Psalm 110,
“The Lord has sworn
and will not change his mind,
“You are a priest forever
after the order of Melchizedek.”” (Ps 110:4)
The book of Hebrews explains this exquisitely:-
“Since then we have a great high priest who has passed through the heavens, Jesus, the Son of God, let us hold fast our confession. 15 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. 16 Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need.
For every high priest chosen from among men is appointed to act on behalf of men in relation to God, to offer gifts and sacrifices for sins. 2 He can deal gently with the ignorant and wayward, since he himself is beset with weakness.3 Because of this he is obligated to offer sacrifice for his own sins just as he does for those of the people. 4 And no one takes this honor for himself, but only when called by God, just as Aaron was.
5 So also Christ did not exalt himself to be made a high priest, but was appointed by him who said to him,
“You are my Son, today I have begotten you”;
6 as he says also in another place,
“You are a priest forever, after the order of Melchizedek.”
7 In the days of his flesh, Jesus offered up prayers and supplications, with loud cries and tears, to him who was able to save him from death, and he was heard because of his reverence. 8 Although he was a son, he learned obedience through what he suffered. 9 And being made perfect, he became the source of eternal salvation to all who obey him, 10 being designated by God a high priest after the order of Melchizedek.” (Heb 4:14 – 5:10)
This day of Advent, let us reflect upon our eternal High Priest who made the perfect sacrifice for the sin of the world.