ה֥וֹי הַמִּתְאַוִּ֖ים אֶת־י֣וֹם יְהוָ֑ה לָמָּה־זֶּ֥ה לָכֶ֛ם י֥וֹם יְהוָ֖ה הוּא־חֹ֥שֶׁךְ וְלֹא־אֽוֹר׃
Woe unto you that desire the day of the LORD! Wherefore would ye have the day of the LORD? It is darkness, and not light.
Read halakhic rulings (Jewish law) on Amos 5:18: and classical halakhic sources.