"That is not possible!" or "Certainly not!" This expression strongly denies that this could happen. You may have a similar expression in your language that you could use here.
Paul speaks about God's talking with Moses as if it is being done in the present time. AT: "For God said to Moses" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Paul speaks of a person who does good things in order to gain God's favor as if that person were running a race. (See: [[rc://en/ta/man/translate/figs-metaphor]])