They would agree to give their power to the beast, but it would not be that they want to obey God. Alternate translation: "For God has put it into their hearts to agree to give ... until God's words are fulfilled, and by doing this, they would carry out God's purpose"
Here "heart" is a metonym for desires. Making them want to do something is spoken of as putting it in their hearts to do it. Alternate translation: "God has made them want" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
This can be stated in active form. Alternate translation: "until God fulfills what he said will happen" (See: [[rc://en/ta/man/translate/figs-activepassive]])