A priest, in the Old Testament sense, had several duties. He was to approach God on behalf of man. He was appointed, as the book of Hebrews says, "to offer gifts and sacrifices."
Jesus is the permanent High Priest, who continues, we are told, by the power of an indestructible life. He offered up Himself as a sacrifice for sins, we are told further, and that sacrifice is permanent, perfect, and brings complete salvation to all who come to God through Him. This is what we are told at large in Hebrews 7 & 8.
There is a great deal of information in the Old and New Testaments about what theologians refer to as the "substitutionary atonement," and the idea goes somewhat like this:
The sacrifice of animals was accepted, under the Old Testament system, as a "covering over" of sin--so that if you committed a sin, you brought your animal to the priest, and he would kill it, offer it to God, and then you and he would share (in some cases) in eating it. Under the Old Testament system, this was not optional. It was required.
All these Old Testament sacrifices were preparatory and pictorial--they showed what Jesus would eventually do, ONCE, at the end of the ages, when He sacrificed Himself. His death is deemed to be the ultimate sacrifice--adequate for all sinners and all sins. Thus John says, "He is the atoning sacrifice, not for our sins only, but for the sins of the whole world."
The idea is that when Jesus died, "He carried our iniquities (sins)," and that He was the "Lamb of God, who takes away the sin of the world."
This is intimately bound up with the concept of His Priesthood--that He actually stands before God, as the permanent and perfect Offering, as well as being the Offeror. This is all very theological, but the summary is this:
Jesus died to take away your sins, if you will believe in Him. He wants to do that. He wants YOU to have His righteousness, which is your admission ticket into heaven. You can only get there with His righteousness. Your own is not enough, and your sins will condemn you. However, when you believe in Jesus, many things happen, all at once. Your sins are forgiven. You are given His righteousness. You receive everlasting life. Your direction changes. Where before you were moving toward perishing forever, you now are on the way to Heaven.
This is the greatest opportunity of all time. Want to live forever? Want to be free of the burden of your sins? Want to spend eternity in Heaven?
Believe in Jesus. He will accept you, right now.
Ever wonder what God might have to say to YOU today? Here are things to ponder, and things to receive into your heart. If you have a question, put it in the comments. I respond as much as I can.
A note for all my readers: I've been experimenting with YouTube videos for Bible teaching for a while, and I'm working through Revelation here. My YouTube videos are currently short studies in Matthew, and at present I'm posting videos on Revelation as well. Both appear on the blog, which is turning into a Vlog. I encourage you to subscribe to my YouTube channel for better coverage.