(Jesus) said to them again, "Peace be with you. As the Father has sent me, so I send you." And when he had said this, he breathed on them and said to them, "Receive the Holy Spirit. Whose sins you forgive are forgiven them, and whose sins you retain are retained." [JN 20:21-23]
There is no need for a priesthood to offer sacrifices.
Jesus shed blood was enough and put an end to the system of sacrifices.
God put an amazing amount of power in the hands of easily corruptible mortal man.
God promises us this......
1 John 1:7-9 7 But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. 8 If we say we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he [He who? Jesus.] is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
1 Timothy 2:5-6 5 For there is one God, and there is one mediator between God and men, the man Christ Jesus, 6 who gave himself as a ransom for all, which is the testimony given at the proper time.
If God gave men the power to retain sins then He contradicted His own word which promises forgiveness.
Acts 15:8 And God, who knows the heart, bore witness by granting them the holy Spirit just as he did us. 9 He made no distinction between us and them, for by faith he purified their hearts.