Kabbalah for Pirkei Avot 5:9
חַיָּה רָעָה בָאָה לָעוֹלָם עַל שְׁבוּעַת שָׁוְא, וְעַל חִלּוּל הַשֵּׁם. גָּלוּת בָּאָה לָעוֹלָם עַל עוֹבְדֵי עֲבוֹדָה זָרָה, וְעַל גִלּוּי עֲרָיוֹת, וְעַל שְׁפִיכוּת דָּמִים, וְעַל הַשְׁמָטַת הָאָרֶץ. בְּאַרְבָּעָה פְרָקִים הַדֶּבֶר מִתְרַבֶּה, בָּרְבִיעִית, וּבַשְּׁבִיעִית, וּבְמוֹצָאֵי שְׁבִיעִית, וּבְמוֹצָאֵי הֶחָג שֶׁבְּכָל שָׁנָה וְשָׁנָה. בָּרְבִיעִית, מִפְּנֵי מַעְשַׂר עָנִי שֶׁבַּשְּׁלִישִׁית. בַּשְּׁבִיעִית, מִפְּנֵי מַעְשַׂר עָנִי שֶׁבַּשִּׁשִּׁית. וּבְמוֹצָאֵי שְׁבִיעִית, מִפְּנֵי פֵרוֹת שְׁבִיעִית. וּבְמוֹצָאֵי הֶחָג שֶׁבְּכָל שָׁנָה וְשָׁנָה, מִפְּנֵי גֶזֶל מַתְּנוֹת עֲנִיִּים:
Savage beasts come to the world because of vain [i.e., unneeded] oaths, desecration of the Name, [i.e., transgressing blatantly in public, or being seen by others, who emulate one's deeds]. Exile comes to the world because of idolators, illicit relations, bloodshed and (not) leaving the land idle [i.e., plowing and sewing on the sabbatical year]. In four periods pestilence increases: in the fourth year (of shemitah), and in the seventh year, and at the conclusion of the seventh year, and at the conclusion of the festival (of Succoth) of every year. In the fourth year, because of (omission of) the poor-tithe of the third year. [For in place of the second tithe of the other years of shemitah, in the third and in the sixth years the poor-tithe is given]. In the seventh year, because of (omission of ) the poor-tithe of the sixth year. At the conclusion of the seventh year, because of (profanation of) the fruits of the seventh year, and at the conclusion of the festival of every year, because of theft of the gifts of the poor: [leket, shikchah, peah, peret, and oleloth].