This podcast gives a few examplesof how the Messenger Malach מַלְאַ֧ךְ in the Hebrew Bible represented or “was” the One  who Sent him

See also, podcast #130 “Agency in the Bible: The Human Person Jesus “was” the Father”

https://youtu.be/s8FqSysuUGY

Theprinciple or practice of the מַלְאַ֧ךְ malach messenger, the one sent.

Understanding the Messenger principle is crucial to understanding how many “persons” God is. TheMessenger principle, both as a concept and a reality, means that a person’s messenger—theone sent—is regarded as the sender himself.

The proverbialHebrew statement about the Messenger Principle is “השליח שווה לשולחו”the one sent (a messenger) is equal to his sender.” The equality of the onesent to his sender is neither an equality of essence nor of individual one-to-oneidentity. Everyone understood that the messenger was not literally the sameperson nor the same being as the sender. Rather, the messenger was given thesender's full authority to speak and act on his behalf. The messenger carried authorityfrom the sender and was therefore to be regarded as the sender himself.

Old Testament scholar John Walton highlights aspects of messenger/agency in the ZondervanIllustrated Bible Backgrounds Commentary when discussing the firstappearance of the angel (messenger) of Yahweh in Genesis 16 (to Hagar in thewilderness). Walton explains:

In the ancient world direct communication between important parties was ararity. Diplomatic and political exchange usually required the use of anintermediary, a function that our ambassadors exercise today. The messenger whoserved as the intermediary was a fully vested representative of the partyhe represented. He spoke for that party and with the authority of thatparty. He was accorded the same treatment as that party wouldenjoy were he there in person. While this was standard protocol,there was no confusion about the person’s identity (emphasis mine).[1]

Judges11:12

Jephthahsent messengers to the king of the sons of Ammon, saying,"What is between you and me, that you have come to me tofight against my land?"

  וַיִּשְׁלַ֤ח יִפְתָּח֙ מַלְאָכִ֔ים אֶל־מֶ֥לֶךְ בְּנֵֽי־עַמּ֖וֹן לֵאמֹ֑רמַה־לִּ֣י וָלָ֔ךְ כִּֽי־בָ֥אתָ אֵלַ֖י לְהִלָּחֵ֥ם בְּאַרְצִֽי׃

2 Kings3:7  (King Jehoram son of Ahaz after Ahabdied and Moab revolted)

Then he(Jehoram) went and sent to Jehoshaphat king of Judah, saying, "Theking of Moab has rebelled against me. Will you go with me tofight against Moab?" And he said, "I will go up; I am as youare, my people as your people, my horses as yourhorses." 

  וַיֵּ֡לֶךְ וַיִּשְׁלַח֩אֶל־יְהוֹשָׁפָ֙ט מֶֽלֶךְ־יְהוּדָ֜ה לֵאמֹ֗ר מֶ֤לֶךְ מוֹאָב֙ פָּשַׁ֣ע בִּ֔יהֲתֵלֵ֥ךְ אִתִּ֛י אֶל־מוֹאָ֖ב לַמִּלְחָמָ֑ה וַיֹּ֣אמֶר אֶעֱלֶ֔הכָּמ֧וֹנִי כָמ֛וֹךָ כְּעַמִּ֥י כְעַמֶּ֖ךָ כְּסוּסַ֥י כְּסוּסֶֽיךָ׃

1 Samuel 16:19

Saul sent messengers to Jesse, and he said, "Send to meyour son David who is with the flock."

  וַיִּשְׁלַ֥ח שָׁא֛וּל מַלְאָכִ֖יםאֶל־יִשָׁ֑י וַיֹּ֕אמֶר שִׁלְחָ֥ה אֵלַ֛י אֶת־דָּוִ֥ד בִּנְךָ֖ אֲשֶׁ֥רבַּצֹּֽאן׃

Isa7:10

AndYHVH continued speaking to Ahaz, saying,

  וַיּ֣וֹסֶף יְהוָ֔ה דַּבֵּ֥ר אֶל־אָחָ֖זלֵאמֹֽר׃