Therefore John was saying to the crowds that came out to be immersed by him, "You brood of vipers! Who warned you to flee from the coming wrath?"
Luke 3:7

Who warned the Jews of John's day to flee the coming wrath? Moses, Isaiah, and a half-dozen others did. They read and taught Moses, but they lived their own traditions without believing Moses, or they would have believed John and Yeshua.

Isaiah 40:2 says that before Messiah finally restores Israel, that they would be repaid double for their sins. For all they have suffered, there must be more to come because that restoration has not yet been delivered.