The Catholic Church has priest because Jesus established the NT priesthood. I direct you to the following:
Did Jesus Give Priests to the Church?
By Kenneth J. Howell
catholic.com/thisrock/2004/0404sbs.asp
In the OT, the structure of the priesthood looked like this:
- Aaron, high priest
- Levites, ministerial priests
- Israel, a nation of priests
We see a similar structure in the NT. Check out the passage on the Ministerial Priesthood below concerning Paul’s reference to the NT priesthood.
The New Testament Priesthood Proved from Scripture
Jesus, Our Eternal High Priest
“Therefore, since we have a great high priest who has passed through the heavens, Jesus the Son of God, let us hold fast our confession.” (Hebrews 4:14)
The Ministerial Priesthood
“But I have written very boldly to you on some points so as to remind you again, because of the grace that was given me from God, to be a minister of Christ Jesus to the Gentiles, ministering as a priest the gospel of God, so that my offering of the Gentiles may become acceptable, sanctified by the Holy Spirit.” (Romans 15:15-16)
The Universal Priesthood of All Belivers
“But you are a chosen people, a royal priesthood, a holy nation, a people belonging to God, that you may declare the praises of him who called you out of darkness into his wonderful light.” (1 Peter 2:9)
Additionally, we find that the Apostle Paul himself forgave the sins of others acting
in persona Christi or “in the person of Christ” – just as the Catholic Church teaches concerning the sacrament of reconciliation.
2 Corinthians 2:10
10To whom ye forgive any thing, I forgive also: for if I forgave any thing, to whom I forgave it, for your sakes forgave I it
in the person of Christ; (KJV)
And to whom you have pardoned any thing,
I also. For, what I have pardoned, if I have pardoned any thing, for your sakes have I done it in the person of Christ. (Douay Rheims)