Paul famously quotes Habakkuk in Galatians 3 to clinch his point that it’s no good going back to Torah. The false teachers were telling the Galatians that in addition to believing in Messiah Jesus, they needed to be circumcised and enter Israel and live by Torah. Paul says, no, Torah is over, Israel no longer has a separate role in the world, the old world of sacred days, foods, and places has passed away, and now Jew and Gentile alike approach God directly in Christ. In fact, the expiration date on Israel will soon be manifested to the world, as the people would be slaughtered and driven away, and the temple, priesthood, and sacrifices all disappear once and for all in 70 A.D. in the destruction of Jerusalem.
The Habakkuk quote is especially apt. It is much more than a proof text of faith vs. works. Habakkuk faced much the same circumstance as Jerusalem did in Paul’s day: a corrupt priesthood, national apostasy, and looming judgment. The armies of Babylon were just over the horizon, and they were running the table, capturing city after city, conquering kingdom after kingdom. Israel was on their list, and faced the impending slaughter and taking away of the people, and the loss of the temple, the priesthood, and the sacrifices.
But God’s message to the prophet is, “when I take away the temple and the city, all is not lost. The just shall live by his faithfulness.”
Same to you, Galatians. You do NOT need to be circumcised and get into Israel and commit to Torah. That is over in Christ, and soon will disappear completely from history. Believe in Jesus: his faithfulness has satisfied God completely, and in Christ, you have everything.