This can be stated in active form. AT: "the law held us captive and we were in prison" or "the law held us captive in prison" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The way the law controlled us is spoken of as if the law were a prison guard holding us as captives. AT: "the law controlled us like a prison guard" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This can be stated in active form, and who this faith is in can be stated clearly. AT: "until God would reveal that he justifies those who have faith in Christ" or "until God would reveal that he justifies those who trust in Christ" (See: [[rc://en/ta/man/translate/figs-activepassive]] and [[rc://en/ta/man/translate/figs-explicit]])
More than simply "one who gives oversight to a child," this was usually a slave who was responsible for enforcing rules and behaviors given by the parent and would report to the parent on the child's actions.
Before Christ came, God had planned to justify us. When Christ came, he carried out his plan to justify us. This can be stated in active form. AT: "so that God would declare us to be righteous" (See: [[rc://en/ta/man/translate/figs-activepassive]])