That is what Paul's Church teaches but it isn't what is taught in the OT. God proclaimed that no other person can atone for your sins, it is up to each and every person to atone and live as God would have you live: love for God and neighbor, showing mercy, kindness and help for the strangers who you encounter, caring for the sick and elderly and orphans. The 'virtues' Paul wrote of (IF he really did write that letter- only 7 or 8 have been 'confirmed' to have been written by him), so he wasn't too far off the truth of what God wants from us, other than the claim that Jesus died for our sins. God never wanted blood sacrifices - and certainly didn't want a man to be a blood sacrifice- that's what pagan religions required. He only wants humans to love Him and each other.

"Join the celebration". Of course, as soon as you accept God into your heart and life rather than worshipping a man who came to teach that message to people.

Then you can follow this proclamation from the Prophet: "This is the day God has given you; let us rejoice and be glad in it".