|Metropolitan Museum of Art|
The Angel Gabriel Appearing to Zacharias
"For who hath despised the day of small things? for they shall rejoice, and shall see the plummet in the hand of Zerubbabel with those seven; they are the eyes of the LORD, which run to and fro through the whole earth."
The scenario of the Hebrews being returned from captivity supplied symbolic meaning which enhanced Blake's myth. Divine Guidance being provided; the activity of the eyes of God throughout the earth; and the temple being successfully rebuilt were aspects of the return from Babylon which contributed to Blake's myth of fall and return.
Although Blake does not mention Zechariah as one on his Old Testament sources, Ezra is named as a prophet who influenced his childhood. Ezra like Zechariah recounts the story of the struggle to rebuild Jerusalem and regain independence. The period of the Babylonian Captivity was over 50 years.
When the seventh month came, and the sons of Israel were in the towns, the people gathered as one man to Jerusalem.
 Then arose Jeshua the son of Jo'zadak, with his fellow priests, and Zerub'babel the son of She-al'ti-el with his kinsmen, and they built the altar of the God of Israel, to offer burnt offerings upon it, as it is written in the law of Moses the man of God.
 But now for a brief moment favor has been shown by the LORD our God, to leave us a remnant, and to give us a secure hold within his holy place, that our God may brighten our eyes and grant us a little reviving in our bondage.
 For we are bondmen; yet our God has not forsaken us in our bondage, but has extended to us his steadfast love before the kings of Persia, to grant us some reviving to set up the house of our God, to repair its ruins, and to give us protection in Judea and Jerusalem.
 For behold, upon the stone which I have set before Joshua, upon a single stone with seven facets, I will engrave its inscription, says the LORD of hosts, and I will remove the guilt of this land in a single day.
 In that day, says the LORD of hosts, every one of you will invite his neighbor under his vine and under his fig tree.
 And I said to the angel who talked with me, "What are these, my lord?"
 Then the angel who talked with me answered me, "Do you not know what these are?" I said, "No, my lord."
 Then he said to me, "This is the word of the LORD to Zerub'babel: Not by might, nor by power, but by my Spirit, says the LORD of hosts.
 What are you, O great mountain? Before Zerub'babel you shall become a plain; and he shall bring forward the top stone amid shouts of `Grace, grace to it!'"
 Moreover the word of the LORD came to me, saying,
 "The hands of Zerub'babel have laid the foundation of this house; his hands shall also complete it. Then you will know that the LORD of hosts has sent me to you.
 For whoever has despised the day of small things shall rejoice, and shall see the plummet in the hand of Zerub'babel."These seven are the eyes of the LORD, which range through the whole earth."
Here is a quote from the Wikipedia entry for Zerubbabel.
"According to the Book of Ezra chapter 2, Zerubbabel returned to Jerusalem in the first wave of liberated exiles under the decree of King Cyrus of Persia in 538 BCE. The mention of Zerubbabel in the book of Ezra primarily serves the purpose of describing the return to Judah following the exile from Babylon and the construction of the Second Temple."
Letters, (E 707) "To My Dearest Friend John Flaxman these lines I bless thee O Father of Heaven & Earth that ever I saw Flaxmans face Angels stand round my Spirit in Heaven. the blessed of Heaven are my friends upon Earth When Flaxman was taken to Italy. Fuseli was giv'n to me for a season And now Flaxman hath given me Hayley his friend to be mine such my lot upon Earth Now my lot in the Heavens is this; Milton lovd me in childhood & shewd me his face Ezra came with Isaiah the Prophet, but Shakespeare in riper years gave me his hand Paracelsus & Behmen appeard to me. terrors appeard in the Heavens above"
Milton, Plate 6, (E 99) "The Surrey hills glow like the clinkers of the furnace: Lambeths Vale Where Jerusalems foundations began; where they were laid in ruins Where they were laid in ruins from every Nation & Oak Groves rooted Dark gleams before the Furnace-mouth a heap of burning ashes When shall Jerusalem return & overspread all the Nations Return: return to Lambeths Vale O building of human souls Thence stony Druid Temples overspread the Island white And thence from Jerusalems ruins.. from her walls of salvation And praise: thro the whole Earth were reard from Ireland To Mexico & Peru west, & east to China & Japan; till Babel The Spectre of Albion frownd over the Nations in glory & war All things begin & end in Albions ancient Druid rocky shore But now the Starry Heavens are fled from the mighty limbs of Albion" Jerusalem, Plate 43 , (E 191) "and Jerusalem is taken! The City of the Woods in the Forest of Ephratah is taken! London is a stone of her ruins; Oxford is the dust of her walls! Sussex & Kent are her scatterd garments: Ireland her holy place! And the murderd bodies of her little ones are Scotland and Wales The Cities of the Nations are the smoke of her consummation The Nations are her dust! ground by the chariot wheels Of her lordly conquerors, her palaces levelld with the dust I come that I may find a way for my banished ones to return Fear not O little Flock I come! Albion shall rise again. So saying, the mild Sun inclosd the Human Family. Forthwith from Albions darkning [r]ocks came two Immortal forms Saying We alone are escaped. O merciful Lord and Saviour, We flee from the interiors of Albions hills and mountains! From his Valleys Eastward: from Amalek Canaan & Moab: Beneath his vast ranges of hills surrounding Jerusalem."
Here are other posts concerning the Eyes of God.