Catechism of the Summa (22)

 (D)

The will of man then is the central point of all those acts that constitute his life as a rational being, and have direct bearing upon the reward of his life which is the winning or the losing of the happiness of heaven?

Yes, the will of man is the central point of all those acts that constitute his life as a rational being, and have direct bearing upon the reward of his life which is the gain or the loss of the happiness of heaven; and this implies that the act of a human being is of no account except in so far as it proceeds from the will; whether it be the will itself that produces the act, or whether the will move some other faculty of the soul or even member of the body to produce the act

Of all the interior acts of the will which is the most important and the one which is the root of responsibility in man?

It is the act of choosing or "choice" 

Why has the act of choosing or "choice" this importance?

It is because this act effects that the will fixes with full knowledge and after deliberation upon some determined good, which it accepts and makes its own in preference to any other 

Is choice properly speaking the act of the free will?

Yes 

It is then by the choice that he makes with regard to all things that man derives his true moral character and his real value in view of the gain or the loss of his eternal happiness?

Yes, it is by the choice that he makes in regard to all things that man derives his true moral character and his real value in view of the gain or the loss of his eternal happiness.

How is choice divided as regards man's true character and moral worth in view of the gain or loss of his eternal happiness?

It is divided into "good choice" and "bad choice" 

What is a "good choice"?

It is one that bears upon a good object, in view of some good end, and as regards which all the accompanying. circumstances are good

(E)

Whence is derived the goodness of an object, of an end, and of the circumstances?

This goodness is derived from the relation that all these things have with right reason 

What is meant by right reason?

By this is understood the reason enlightened by all the lights that come from God, or which at least is not knowingly at variance with them.

When man then wills or chooses something in conformity with right reason for an object or an end of which right reason approves, and of which all the accompanying circumstances accord with right reason, the act willed or chosen man is a good act?

Yes; then, and then only, is man's act a good act. on any one of these counts whatsoever man's act is conformed with right reason it ceases to be a good and it becomes in a less or great degree, as the case be, a bad act 

What is a bad act called?

A bad act is called a "fault" or a "sin" 

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