Йешайау 55:1 Каббала: Sefer HaBahir

ה֤וֹי כָּל־צָמֵא֙ לְכ֣וּ לַמַּ֔יִם וַאֲשֶׁ֥ר אֵֽין־ל֖וֹ כָּ֑סֶף לְכ֤וּ שִׁבְרוּ֙ וֶֽאֱכֹ֔לוּ וּלְכ֣וּ שִׁבְר֗וּ בְּלוֹא־כֶ֛סֶף וּבְל֥וֹא מְחִ֖יר יַ֥יִן וְחָלָֽב׃

Но все жаждущие придут за водой, а у кого нет денег; Приди, купи и ешь; Да, приходи, покупай вино и молоко Без денег и без цены.

Sefer HaBahir

His students asked Rabbi Berachiah, "Accept our words before you!" He did not give them permission. One time, he did give them permission, but he* did this to check whether now they could direct their souls. "The first day," he examined them and said, "Let me hear your wisdom."
They opened and said, "'In the beginning' (Genesis 1:1) is one. [Two is:] 'Spirit that will wrap itself is from before me; souls I made' (Isaiah 57:16). [Three is:] 'The brook [פלג] of Elohim is filled with water' (Psalms 65:10)."
[Rabbi Berachiah asked them,] "What is 'brook'?"
[They answered,] "You taught us, our rabbi,** that [God] took waters of creation and divided them, gave half in the heavens and half in the ocean sea, as is written, 'The brook of Elohim is filled with water' — and through it, a person learns Torah. As rabbi Chama said, 'Through the merit of gemilut chasadim a person learns Torah. Similarly, it is written, All who are thirsty, go to water, and if he has no money [כסף], go, obtain food and eat' (Isaiah 55:1) — go to Him and He will bestow kindness to you: obtain*** and eat!'"
*[Ed. - Sefaria text reads "she," but other versions say, "he."]
**[Ed. - Sefaria text reads "we saw"; other versions of the text say "our rabbi."]
***[alternatively, 'hope.' For example, see Nehemiah 2:13, 15; Psalms 119:166, 145:15; Esther 9:1]

Sefer HaBahir

[Rabbi Berachiah responded,] “Another interpretation: ’And if he has no silver [כסף], go to him’ (Isaiah 55:1) — [go to Him,] because He has silver! As is written, ’To me is the silver and to me is the gold’ (Chaggai 2:8). What is ’Mine is the silver and Mine is the gold’? A parable, to which this is similar: to a king who has two treasure houses, one of silver and one of gold. The name of the silver was in his right and that of gold was in his left. He said, ‘This [the silver] will be available and easy to bring out.’ He makes his words gentle, and cleaves to the poor, and directs them with calm, as is written, ’Your right hand, YHVH, glorious in strength’ (Exodus 15:6). And if one is happy with his portion — good — but if not, ’Your right hand, YHVH shatters the enemy’ (Exodus 15:6)."
[The students asked,] "What is ’Your right hand, YHVH shatters the enemy’?”
He said to them, “This is the gold, as is written, ’Mine is the silver and Mine is the gold.’”