The prohibition against preaching is to keep people from organizing into groups to impose their beliefs on others.
When rules are made for the many, they're cruel for the few.
To be courageous is to do what's right even in the face of impossible odds.
If there comes among you a prophet saying 'Let us return to the darkness,' you shall stone him, because he has sought to thrust you away from the light.
Ideas combined with courage can change the world.