Daily Zohar 4389
Holy Zohar text. Daily Zohar -4389

Hebrew translation:

161. וּבֹא וּרְאֵה, טֶרֶם שֶׁנִּמּוֹל אַבְרָהָם זַרְעוֹ לֹא הָיָה קָדוֹשׁ, מִשּׁוּם שֶׁיָּצָא מִתּוֹךְ עָרְלָה וְהִדְבַּק בָּעָרְלָה לְמַטָּה. אַחַר שֶׁנִּמּוֹל, יָצָא אוֹתוֹ הַזֶּרַע בְּתוֹךְ הַקְּדֻשָּׁה, וְנִדְבַּק בַּקְּדֻשָּׁה שֶׁלְּמַעְלָה וְהוֹלִיד לְמַעְלָה, וְנִדְבַּק אַבְרָהָם בְּדַרְגָּתוֹ כָּרָאוּי. בֹּא רְאֵה, כְּשֶׁהוֹלִיד אַבְרָהָם אֶת יִצְחָק, יָצָא קָדוֹשׁ כָּרָאוּי. וְאֵלּוּ [וַדַּאי] הַמַּיִם שֶּׁהָרוּ וְהוֹלִידוּ חֹשֶׁךְ.
162. רַבִּי אֶלְעָזָר שָׁאַל יוֹם אֶחָד אֶת רַבִּי שִׁמְעוֹן אָבִיו. אָמַר לוֹ, זֶה שֶׁקָּרָא לוֹ הַקָּדוֹשׁ בָּרוּךְ הוּא יִצְחָק, שֶׁכָּתוּב וְקָרָאתָ אֶת שְׁמוֹ יִצְחָק, לָמָּה? שֶׁהֲרֵי נִרְאֶה שֶׁעַד שֶׁלֹּא יָצָא לָעוֹלָם קָרָא לוֹ יִצְחָק?
163. אָמַר לוֹ, הֲרֵי נֶאֱמַר שֶׁאֵשׁ לוֹקַחַת מַיִם, שֶׁהֲרֵי הַמַּיִם בָּאִים מִצַּד שֶׁל הַגְּבוּרָה, וְעוֹד [נ”א וּבֹא תִשְׁאַל מֵהַלְוִיִּם] [שָׁאַל אוֹתוֹ] הַלְוִיִּם שֶׁהֵם מְשַׂמְּחִים לְאוֹתוֹ הַצַּד בִּכְלֵי זֶמֶר וְתִשְׁבָּחוֹת כְּנֶגֶד הַצַּד הַזֶּה, מִשּׁוּם כָּךְ יִצְחָק הוּא חֶדְוָה, מִשּׁוּם שֶׁהוּא בָּא מֵאוֹתוֹ צַד וְנִדְבָּק בּוֹ.


Zohar Vayera
Continued from previous DZ
The seeds of Abraham were not holy until he was circumcised. Because he came out from inside a foreskin and stuck to the foreskin below, after he was circumcised, the seed came out from inside a holy man that was attached to the holiness and his level, which is Chessed. When Abraham gave birth to Isaac, he came out holy as he should be. This water, which is Abraham and Chessed, conceived and gave birth to Isaac, is the aspect of Left and darkness before he was dressed with the Chassadim of Abraham.
Since Isaac came from Abraham and dressed in his Chassadim, he became light.

Rabbi Elazar asked Rabbi Shimon, his father. The Holy One, Blessed be He, called him Isaac (יִצְחַק) before he was born, as it is written;
Genesis 17:19
“וַיֹּאמֶר אֱלֹהִים אֲבָל שָׂרָה אִשְׁתְּךָ יֹלֶדֶת לְךָ בֵּן וְקָרָאתָ אֶת שְׁמוֹ יִצְחָק וַהֲקִמֹתִי אֶת בְּרִיתִי אִתּוֹ לִבְרִית עוֹלָם לְזַרְעוֹ אַחֲרָיו.”
“Then God said: “No, Sarah, your wife shall bear you a son, and you shall call his name Isaac; I will establish My covenant with him for an everlasting covenant, and with his descendants after him.”
There was no reason for this name to mean ‘made laugh’ until Sarah said later,
Genesis 21:6
“וַתֹּאמֶר שָׂרָה צְחֹק עָשָׂה לִי אֱלֹהִים כָּל הַשֹּׁמֵעַ יִצְחַק לִי.”
“And Sarah said, “God has made me laugh, and all who hear will laugh (יִצְחַק, Isaac) with me.”

He said to him, we have learned that fire, which is Left, and Gevurah, took water, which is Right, and Chassadim. Water that comes from the side of Gevurah means that the Left and the Right were included in each other. Then, the Left side has the aspect of wine that pleases God and people. The Levites, who are drawn from the Left line, make the Left happy with musical instruments and praises that are also drawn from the left side. Because of this, Isaac is joy and laughter, and because he came from this side, that is, from the left side, he clung to it.

We can understand from the above that the name of a person is determined by Hashem before the parents choose their child’s name.