In this case, the "angel of the LORD" is different from the "Angel of the LORD" in other places clearly identified as the LORD, such as Gen 16:7-13, 22:11-17, 32:24-30, 48:16, Ex 3:2-6, 32:34, Num 22:22-35, Josh 5:13-15, Judg 2:1-4, 6:11-23, 13:3-23, Isa 63:9, Dan 3:25, 28, Hos 12:4, 5, Zech 3:1-7, Mal 3:1.
That is, this angel in Zech 1 appears to be an angel as distinct from the LORD for the following reasons:
- He is addressed as "Lord" אָדוֹן , adoni, V9.
- In V13 he is called and angel and not "angel of the LORD" - this never occurs in the other cases where "Angel of the LORD" is the LORD.
APPENDIX - Other interesting places where similar references occur
Note the following instances suggesting interesting characteristics of the LORD.
- Zech 2:6-12 – the LORD (= YHWH) claims three times that He has been sent by the LORD.
- Isa 48:11-16 – again, the LORD has been sent by the LORD.
- Isa 63:7-16 – the LORD (described as a Father) sends His divine servant (the angel of His presence) and His Holy Spirit who is grieved (compare Ps 78:40).
- Hos 1:7 – the LORD saves by the LORD their God.
- Prov 30:1-4 – the Son of God is as unfathomable as God Himself.
In the following references, "Angel of God" is the LORD Himself.
Gen 6:13, 8:15, 9:8, 17, 15:13, 17:3, 4, 21:12, 16-21, 35:1, 10, Ex 4:3-8, 6:2, 23:20, 21, Deut 1:6, 1 Kings 12:22.