Isaiah 13:9-11, “Howl, for the day of יהוה is near! It comes as a destruction from the Almighty. Therefore all hands go limp, every man’s heart melts, and they shall be afraid. Pangs and sorrows take hold of them, they are in pain as a woman in labor; they are amazed at one another, their faces aflame! See, the day of יהוה is coming, fierce, with wrath and heat of displeasure, to lay the earth waste, and destroy its sinners from it. For the stars of the heavens and their constellations do not give off their light. The sun shall be dark at its rising, and the moon not send out its light. And I shall punish the world for its evil, and the wrong for their crookedness, and shall put an end to the arrogance of the proud, and lay low the pride of the ruthless.”
Ezekiel 13:1-9, "And the word of יהוה came to me, saying, Son of man, prophesy against the prophets of Yisra’yl who prophesy, and say to those who prophesy out of their own heart, ‘Hear the word of יהוה!, "Thus said the Master יהוה, “Woe to the foolish prophets, who are following their own spirit, without having had a vision! O Yisra’yl, your prophets have been like foxes among ruins. You have not gone up into the breaches, nor do you build a wall for the house of Yisra’yl to stand in battle on the day of יהוה, Their visions are false and their divinations a lie, saying, ‘Thus declares יהוה,’ when יהוה has not sent them, yet they expected the word to be confirmed! Have you not seen a false vision, and have you not spoken a divination of lies? You say, ‘יהוה declares,’ when I have not spoken. Therefore thus said the Master יהוה, “Because you have spoken falsehood and seen lies, therefore see, I am against you,” declares the Master יהוה, My hand shall be against the prophets who see falsehood and who divine lies. They shall not be in the council of My people, nor be written in the record of the house of Yisra’yl, and they shall not enter into the land of Yisra’yl. And you shall know that I am the Master יהוה."
Joel 1:14-20, "1:14, "Set apart a fast. Call an assembly, gather the elders, all the inhabitants of the land, into the House of יהוה your Strength, and cry out to יהוה."1:15, "Alas for the day! For the day of יהוה is near, and it comes as destruction from the Almighty."1:16, "Is not the food cut off before our eyes, joy and gladness from the House of our Mighty One?"1:17, "The seed has rotted under their clods, storehouses are laid waste, granaries are broken down, for the grain has withered."1:18, "How the beasts moan! The herds of cattle are restless, because they have no pasture. The flocks of sheep also perish."1:19, "I cry to You יהוה, for fire has consumed the pastures of the wilderness, and a flame has set on fire all the trees of the field."1:20, "Even the beasts of the field cry out to You, for the water streams are dried up, and fire has consumed the pastures of the wilderness."
Joel 2:28-32, "2:28, "“And after this it shall be that I pour out My Spirit on all flesh. And your sons and your daughters shall prophesy, your old men dream dreams, your young men see visions."2:29, "“And also on the male servants and on the female servants I shall pour out My Spirit in those days."2:30, "“And I shall give signs in the heavens and upon the earth: blood and fire and columns of smoke,"2:31, "the sun is turned into darkness, and the moon into blood, before the coming of the great and awesome day of יהוה."2:32, "“And it shall be that everyone who calls on the Name of יהוה shall be delivered.b For on Mount Tsiyon and in Yerushalayim there shall be an escapec as יהוה has said, and among the survivors whom יהוה calls.
Theres are but a few, not even half of the passages that shoe the day of YHWH is His executon of judgment upon the earth's inhabitants. However there is not a single verse saying the day of the Lord or the Lord's day is sunday.