The term used for “angel” can refer to divine and human messengers (for divine, see Genesis 31:11; Exodus 3:2; for human, see 1 Samuel 29:9; 1 Kings 19:7). It can also describe prophets (Haggai 1:13), priests (Malachi 2:7), or ordinary messengers (1 Samuel 23:27). Here in Judges 13:3, Judges 13:6, Judges 13:9, etc., it refers to the divine messenger, the personal manifestation of the Lord himself.
3 And the angel of the LORD appeared to the woman and said to her, “Behold, you are barren and have not borne children, but you shall conceive and bear a son.