GOD always identify himself specifically in the old testament. As shown in Isaiah 44:24 and Isaiah 45:5, making it easy to identify who the message comes from, the author, an angel or GOD himself. Therefore god or Lord without identification makes the message questionable.
Isaiah 44:24 (GOD) GOD identify himself specifically
24 Thus says the LORD, your Redeemer, who formed you from the womb: “I am the LORD, who mate all things, who alone stretched out the heavens, who spread out the earth by myself,
Isaiah 45:5 (GOD) no other GOD beside.
I am the LORD, and there is no other, besides me there is no God;
It is made very clear in the Old Testament who the statement comes from, example in Zechariah 1:1-6. There is the author recording the event, an Angel delivering the message and God where the message comes from. The author made it distinctively clear both LORD and LORD of host refers to God. Where LORD is men/Angel addressing God, while LORD of host is an identification. This way there is no misunderstand on which are men’s word, which are Angels’ and God’s words.
Zechariah 1:1-6 (author, Angel, God)
[author]1 In the eighth month, in the second year of Darius, the word of the LORD came to the prophet Zechariah, the son of Berechiah, son of Iddo, saying, [Angel] 2 “The LORD was very angry with your fathers. 3 Therefore say to them, [God] Thus declares the LORD of hosts: Return to me, says the LORD of hosts, and I will return to you, says the LORD of hosts. 4 Do not be like your fathers, to whom the former prophets cried out, ‘Thus says the LORD of hosts, Return from your evil ways and from your evil deeds.’ But they did not hear or pay attention to me, declares the LORD. 5 Your fathers, where are they? And the prophets, do they live forever? 6 But my words and my statutes, which I commanded my servants the prophets, did they not overtake your fathers? [author] So they repented and said, As the LORD of hosts purposed to deal with us for our ways and deeds, so has he dealt with us.”
Elias, Malachi 4:5-6