What does Judges 13:7 mean?
Manoah's barren wife has come to him with an amazing report (Judges 13:2–6). A man of God who looked like an angel has appeared with an impossible message. Manoah listens as she tells him what the being said.The "angel of the LORD" told her she will conceive and bear a son—news Manoah would have rejoiced over, as well. She was also told not to drink any alcohol or eat anything ceremonially unclean. This matters because the child will be a Nazarite (Numbers 6:1–20) from the womb. Here, she adds a detail not reported in the previous verses: The boy will remain a Nazarite until he dies.
Manoah and his wife likely knew about Nazirite vows, where someone temporarily dedicated themselves to God in a specified way. What's new here is the idea of someone being set apart for that role from conception until death—and without volunteering for the vow.