"And Moses drew near to the thick darkness" (Exodus 20:18). What enabled him to do so? His humility, as it is said, "Now the man Moses was very humble" and so on (Numbers 12:3). Scripture tells us that whoever is humble will in the end cause the Divine Presence to dwell with a person on the earth, as it is said, "For thus says the high and lofty One who inhabits eternity, whose name is Holy: I dwell in the high and holy place, with him also who is of a contrite and humble spirit" (Isaiah 57:15). And it says, "The spirit of the LORD God is upon me, because the LORD has anointed me to bring good tidings to the humble" (Isaiah 61:1). And it says, "For all these things My hand has made, and so all these things came to be, says the LORD; but to this man will I look, to him who is poor and of a contrite spirit" (Isaiah 66:2); "The sacrifices of God are a broken spirit" (Psalms 51:19). But whoever is haughty of heart causes the land to be defiled and the Divine Presence to depart, as it is said, "Him who has a haughty look and a proud heart I cannot endure" (Psalms 101:5). And everyone who is haughty of heart is called an abomination, as it is said, "Everyone who is proud in heart is an abomination to the LORD" (Proverbs 16:5). And one who worships idols is called an abomination, as it is said, "You shall not bring an abomination into your house" (Deuteronomy 7:26). Just as idolatry defiles the land and drives away the Divine Presence, so too whoever is haughty of heart causes the land to be defiled and the Divine Presence to depart. "And Moses drew near to the thick darkness" (Exodus 20:18): within three partitions, darkness, cloud, and thick darkness; darkness on the outside, cloud within, and thick darkness in the innermost place, as it is said, "And Moses drew near to the thick darkness" and so on.
Why Moses Could Approach the Thick Darkness
Yalkut Shimoni on Torah 302:1
וּמֹשֶׁה נִגַּשׁ אֶל הָעֲרָפֶל, מִי גָּרַם לוֹ, עַנְוְתָנוּתוֹ, שֶׁנֶּאֱמַר "וְהָאִישׁ מֹשֶׁה" וְגוֹ'. מַגִּיד הַכָּתוּב שֶׁכָּל מִי שֶׁהוּא עָנָיו, סוֹפוֹ לְהַשְׁרוֹת שְׁכִינָה עִם הָאָדָם בָּאָרֶץ, שֶׁנֶּאֱמַר (ישעיה נז, טו) "כֹה אָמַר רָם וְנִשָּׂא שֹׁכֵן עַד וְקָדוֹשׁ שְׁמוֹ מָרוֹם וְקָדוֹשׁ אֶשְׁכֹּן וְאֶת דַּכָּא וּשְׁפַל רוּחַ", וְאוֹמֵר (שם סא, א) "רוּחַ אֱלֹהִים עָלָי יַעַן מָשַׁח אֹתִי לְבַשֵּׂר עֲנָוִים", וְאוֹמֵר "וְאֶת כָּל אֵלֶּה יָדִי עָשָׂתָה וְגוֹ' וְאֶל זֶה אַבִּיט אֶל עָנִי וּנְכֵה רוּחַ" (תהלים נא, יט) "זִבְחֵי אֱלֹהִים רוּחַ נִשְׁבָּרָה". וְכָל מִי שֶׁהוּא גְּבַהּ לֵב גּוֹרֵם לְטַמֵּא אֶת הָאָרֶץ, וּלְסַלֵּק אֶת הַשְּׁכִינָה, שֶׁנֶּאֱמַר (שם קא, ה) "גְּבַהּ עֵינַיִם וּרְחַב לֵבָב אֹתוֹ לֹא אוּכָל". וְכָל גְּבַהּ לֵב קָרוּי תּוֹעֵבָה, שֶׁנֶּאֱמַר (משלי טז, ה) "תּוֹעֲבַת ה' כָּל גְּבַהּ לֵב". וְעוֹבֵד אֱלִילִים קָרוּי תּוֹעֵבָה, שֶׁנֶּאֱמַר "וְלֹא תָבִיא תוֹעֵבָה אֶל בֵּיתֶךָ", כְּשֵׁם שֶׁאֱלִילִים מְטַמֵּא הָאָרֶץ וּמְסַלֶּקֶת אֶת הַשְּׁכִינָה כָּךְ כָּל מִי שֶׁהוּא גְּבַהּ לֵב, גּוֹרֵם לְטַמֵּא הָאָרֶץ, וּלְסַלֵּק אֶת הַשְּׁכִינָה. וּמשֶׁה נִגַּשׁ אֶל הָעֲרָפֶל, לִפְנִים מִשָּׁלֹשׁ מְחִיצוֹת, חֹשֶׁךְ, עָנָן, וַעֲרָפֶל, חֹשֶׁךְ מִבַּחוּץ, עָנָן מִבִּפְנִים, וַעֲרָפֶל מִלִּפְנַי וְלִפְנִים, שֶׁנֶּאֱמַר וּמֹשֶׁה נִגַּשׁ אֶל הָעֲרָפֶל וְגוֹ'.