The Talmud discusses Hashem wearing tefillin, and asks what is written in Hashem's tefillin — "Who is like Your people Israel, one nation in the land." This passage establishes the idea that Hashem, as it were, takes pride and joy in Israel specifically, a close parallel to the concept of Hashem being 'sameach b'chelko' in Israel.
אֲמַר לֵיהּ רַב נַחְמָן בַּר יִצְחָק לְרַב חִיָּיא בַּר אָבִין: הָנֵי תְּפִילִּין דְּמָרֵי עָלְמָא מָה כְּתִיב בְּהוּ? אֲמַר לֵיהּ ״וּמִי כְּעַמְּךָ יִשְׂרָאֵל גּוֹי אֶחָד בָּאָרֶץ״. וּמִי מִשְׁתַּבַּח קוּדְשָׁא בְּרִיךְ הוּא בְּשִׁבְחַיְיהוּ דְּיִשְׂרָאֵל? אִין, דִּכְתִיב: ״אֶת ה׳ הֶאֱמַרְתָּ הַיּוֹם״. וּכְתִיב: ״וַה׳ הֶאֱמִירְךָ הַיּוֹם״, אָמַר לָהֶם הַקָּדוֹשׁ בָּרוּךְ הוּא לְיִשְׂרָאֵל: אַתֶּם עֲשִׂיתוּנִי חֲטִיבָה אַחַת בָּעוֹלָם, וַאֲנִי אֶעֱשֶׂה אֶתְכֶם חֲטִיבָה אַחַת בָּעוֹלָם. אַתֶּם עֲשִׂיתוּנִי חֲטִיבָה אַחַת בָּעוֹלָם, שֶׁנֶּאֱמַר: ״שְׁמַע יִשְׂרָאֵל ה׳ אֱלֹהֵינוּ ה׳ אֶחָד״, וַאֲנִי אֶעֱשֶׂה אֶתְכֶם חֲטִיבָה אַחַת בָּעוֹלָם״, שֶׁנֶּאֱמַר ״וּמִי כְּעַמְּךָ יִשְׂרָאֵל גּוֹי אֶחָד בָּאָרֶץ״.
Rav Naḥman bar Yitzḥak said to Rav Ḥiyya bar Avin: What is written in the phylacteries of the Master of the world? Rav Ḥiyya bar Avin replied: It is written: “Who is like Your people, Israel, one nation in the land?” (I Chronicles 17:21). God’s phylacteries serve to connect Him, in a sense, to the world, the essence of which is Israel. Rav Naḥman bar Yitzḥak continues: Is the Holy One, Blessed be He, glorified through the glory of Israel? Rav Ḥiyya bar Avin answered: Yes, as indicated by the juxtaposition of two verses; as it is stated: “You have affirmed, this day, that the Lord is your God, and that you will walk in His ways and keep His laws and commandments, and listen to His voice.” And the subsequent verse states: “And the Lord has affirmed, this day, that you are His treasure, as He spoke to you, to keep His commandments” (Deuteronomy 26:17–18). From these two verses it is derived that the Holy One, Blessed be He, said to Israel: You have made Me a single entity [ḥativa] in the world, as you singled Me out as separate and unique. And because of this, I will make you a single entity in the world, and you will be a treasured nation, chosen by God. You have made Me a single entity in the world, as it is stated that Israel declares God’s oneness by saying: “Hear, Israel, the Lord is our God, the Lord is One” (Deuteronomy 6:4). And because of this, I will make you a single entity in the world, unique and elevated with the utterance: “Who is like Your people, Israel, one nation in the land?” Consequently, the Holy One, Blessed be He, is glorified through the glory of Israel whose praises are written in God’s phylacteries.