Jerusalem Talmud Yoma 5.3

משנה: מִשֶּׁנִּיטַּל הָאָרוֹן אֶבֶן הָיְתָה שָׁם מִימוֹת הַנְּבִיאִים הָרִאשׁוֹנִים וּשְׁתִיָיה הָיְתָה נִקְרֵאת גְּבוֹהָ מִן הָאָרֶץ שָׁלשָׁה אֶצְבָּעוֹת וְעָלֶיהָ הָיָה נוֹתֵן:

MISHNAH: From when the Ark was removed there was a stone there from the time of the earlier prophets; it was called Foundation, higher than the ground by three finger widths. On it he deposed it.

הלכה: תַּנֵּי. עַד שֶׁלֹּא נִיטַּל הָאָרוֹן הָיָה נִכְנַס וְיוֹצֵא לְאוֹרוֹ שֶׁלְאָרוֹן. מִשֶּׁנִּיטָל הָאָרוֹן הָיָה מְגַשֵּׁשׁ וְנִכְנָס מְגַשֵּׁשׁ וְיוֹצֵא.

HALAKHAH: It was stated: Before the Ark was hidden he entered and exited by the light of the Ark. After the Ark was removed he was groping and entering, groping and leaving.

אָמַר רִבִּי יוֹחָנָן. לָמָּה נִקְרָא שְׁמָהּ אֶבֶן שְׁתִיָיה. שֶׁמִּמֶּנָּה הוּשְׁתָּה הָעוֹלָם. תַּנֵּי רִבִּי חִיָיה. וְלָמָּה נִקְרָא אֶבֶן שְׁתִיָיה. שֶׁמִּמֶּנָּה הוּשְׁתָּה הָעוֹלָם. כָּתוּב מִזְמוֹר לְאָסָף אֵל אֱלֹהִים י״י דִּבֶּר וַיִּקְרָא אָרֶץ וגו׳. מִצִּיּוֹן מִכְלַל יוֹפִי אֱלֹהִים הוֹפִיעַ. וְאוֹמֵר הִנְנִי יִסַּד בְּצִיּוֹן אָבֶן וגו׳.

Rebbi Joḥanan said, why is it called Foundation Stone? Because on it the world is based. Rebbi Ḥiyya stated: “Why is it called Foundation Stone? Because on it the world is based.. It is written, a psalm of Asaph; the power, God, the Eternal, spoke and called the earth, etc., from Zion, the perfection of beauty, God appears. And it says, behold I founded in Zion a stone, etc.”