Now we know that things which are difficult are not essential; but that things which are essential have been graciously made easy of attainment by God. Wherefore Democritus well says, that “nature and instruction” are like each other. And we have briefly assigned the cause. For instruction harmonizes man, and by harmonizing makes him natural; and it is no matter whether one was made such as he is by nature, or transformed by time and education. The Lord has furnished both; that which is by creation, and that which is by creating again and renewal through the covenant. And that is preferable which is advantageous to what is superior; but what is superior to everything is mind. So, then, what is really good is seen to be most pleasant, and of itself produces the fruit which is desired—tranquillity of soul. “And he who hears Me,” it is said, “shall rest in peace, confident, and shall be calm without fear of any evil.” “Rely with all thy heart and thy mind on God.”