Balaam uses this rhetorical question to tell Balak that he will not be able to do everything that Balak asks him to do. This can be translated as a statement. Alternate translation: "But I have no power to say anything I want" (See: [[rc://en/ta/man/translate/figs-rquestion]])
The message is spoken of as if it is something that God put into his mouth. Alternate translation: "the message that God wants me to say" (See: [[rc://en/ta/man/translate/figs-metaphor]])