Hebrews 10 : 11-18

So, whereas every priest stands daily by the altar offering repeatedly the same sacrifices that can never take away sins, Christ has offered for all times a single sacrifice for sins and has taken His seat at the right hand of God, waiting until God puts His enemies as a footstool under His feet. By a single sacrifice He has brought those who are sanctified to what is perfect forever.

This also was testified by the Holy Spirit. For after having declared : “This is the covenant that I will make with them in the days to come – says the Lord – I will put My Laws in their hearts and write them on their minds.” He says : “Their sins and evil deeds I will remember no more.”

So, if sins are forgiven, there is no longer need of any sacrifice for sins.