In Mark 1, we learn about both John's baptism of repentance and Jesus's proclamation that "the time has come. Repent and believe in the good news!"
John's baptism
And so John the Baptist appeared in the wilderness, preaching a baptism of repentance for the forgiveness of sins. 5 The whole Judean countryside and all the people of Jerusalem went out to him. Confessing their sins, they were baptized by him in the Jordan River.
Jesus's Proclamation
14 After John was put in prison, Jesus went into Galilee, proclaiming the good news of God. 15 “The time has come,” he said. “The kingdom of God has come near. Repent and believe the good news!”
How would Jews have understood this at the time before Jesus's death? It seems like the common understanding is that before His death and resurrection, the only sanctification for sin was through particular forms of sacrifice, based on this passage in Hebrews (NIV):
22 In fact, the law requires that nearly everything be cleansed with blood, and without the shedding of blood there is no forgiveness.
So - other than that God being with us and loving us is clearly excellent news - how would this have been understood in Jesus's time before his death and resurrection?