Early in the Book of Genesis, a mysterious King/Priest named Melchizedek is mentioned. He is said to be the King of Salem, or Peace. He is a picture of Jesus Christ thousands of years before the birth of Christ. This Psalm looks back to Melchizedek but more importantly, looks ahead to Jesus Christ, our eternal priest.

Psalms 110:1-7 (ESV)
The Lord says to my Lord: “Sit at my right hand, until I make your enemies your footstool.” The Lord sends forth from Zion your mighty scepter. Rule in the midst of your enemies! Your people will offer themselves freely on the day of your power, in holy garments; from the womb of the morning, the dew of your youth will be yours. The Lord has sworn and will not change his mind, “You are a priest forever after the order of Melchizedek.” The Lord is at your right hand; he will shatter kings on the day of his wrath. He will execute judgment among the nations, filling them with corpses; he will shatter chiefs over the wide earth. He will drink from the brook by the way; therefore he will lift up his head.

The Hebrew, and all the Versions, except the Arabic, attribute this Psalm to David: nor can this be doubted, as it is thus attributed in the New Testament. We have in it the celebration of some great potentates accession to the crown; but the subject is so grand, the expressions so noble, and the object raised so far above what can be called human, that no history has ever mentioned a prince to whom a literal application of this Psalm can be made. To Jesus Christ alone, to his everlasting priesthood and government, as King of kings and Lord of lords, can it be applied.
—Adam Clarke’s Commentary

When I consider Jesus as a high priest, I always think of the powerful description in the Book of Hebrews:

Hebrews 4:14-16 (ESV)
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. 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. 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.

How are you impacted when you realize that Jesus, the King of the Universe, and the Perfect Eternal Priest, lived among us, experienced everything that we experience, and understands and sympathizes with us?