Judith is a novella, probably from the 2nd century B.C. and reflecting the Maccabean crisis, whose heroine (introduced in chapter 8) is a mash-up of Jael (Judges 4-5), Esther, and Lady Wisdom (Prov 1-9; Sirach 24). In today’s text we’re dropped into the middle of another moment in which—as in Esther and the Maccabean crisis—the survival of the nation is at stake. The villain: Holofernes.
John. I, with many, find the frequent use of Isaiah 6:9-10 in the New Testament (Matt 13:14-15; Mk 4:12; Lk 8:10; Jn 12:40; Acts 28:26-27) deeply puzzling. Two things worth noticing: (1) the Jewish tradition (OT, NT, Mishnah, etc.) affirms both divine and human responsibility without attempting a resolution. (2) Isaiah might be understood as seeing 8th century B.C. Judah in parallel with the Exodus: as God’s judgment then included the hardening of Pharaoh’s heart, so now (an additional reason to repent!). Christian tradition, seeing Jesus as a second/one-greater-than Moses, may have found it particularly appropriate to speak again of divine hardening of this new Moses’ opponents.
All that said, the core of the puzzle remains, both because (1) Scripture elsewhere emphasizes God’s desire that all be saved (e.g., Ezek 33:11; 1 Tim 2:4) and (2) various combinations of the seven deadly sins (recall Holofernes & his modern counterparts) seem more than adequate explanation for human opposition to God.