Beware therefore (blepete oun). The warning is pertinent. Perhaps Paul noticed anger on the faces of some of the rabbis.
Lest there come upon you (mē epelthēi). Second aorist active subjunctive with the negative final conjunction mē.
In the prophets (en tois prophētais). The quotation is from the lxx text of Hab 1:5. The plural here refers to the prophetic collection (Luk 24:44; Act 24:14). “The Jews of Habakkuk’s day had refused to believe in the impending invasion by the Chaldeans, and yet it had come” (Furneaux).