This teaching function of the law would be impossible if man
was not able to actively chose between good and bad.
In the Old Testament it is
explicitly affirmed when the choice of life and death is placed before men.
Deuteronomy 30: 15-18
"Here, then, I have today set before you
life and prosperity, death and doom. If you obey the commandments of the LORD, your
God, which I enjoin on you today,
loving him, and walking in his ways, and
keeping his commandments, statutes and decrees, you will
live and grow numerous, and the LORD, your
God, will bless you
in the land you are
entering to occupy. If, however, you turn away your hearts and will not listen, but are led astray and adore and
serve other gods, I tell you
now that you will certainly perish; you will not have a long life on the land which you are crossing the Jordan to
enter and occupy.