וַיַּ֣עַן בִּלְעָ֗ם וַיֹּ֙אמֶר֙ אֶל־עַבְדֵ֣י בָלָ֔ק אִם־יִתֶּן־לִ֥י בָלָ֛ק מְלֹ֥א בֵית֖וֹ כֶּ֣סֶף וְזָהָ֑ב לֹ֣א אוּכַ֗ל לַעֲבֹר֙ אֶת־פִּי֙ יְהוָ֣ה אֱלֹהָ֔י לַעֲשׂ֥וֹת קְטַנָּ֖ה א֥וֹ גְדוֹלָֽה׃
And Balaam answered and said unto the servants of Balak: ‘If Balak would give me his house full of silver and gold, I cannot go beyond the word of the LORD my God, to do any thing, small or great.
Read kabbalistic (mystical) interpretation of Numbers 22:18: and classical mystical sources.