nature of the outward act is always dependent upon the character of the inward desire. As is the root, so is the tree. And since whatever acts a man outwardly does he first imagines internally, and, thinking over them, performs them in thought and desire, therefore in order rightly to judge and reward or punish a man's conduct, it is not enough that another person should be aware of his outward deed merely, but rather it is necessary that he should know his intention also, that is, the thought and desire with which he did the deed. And, since one man does not know the heart of another, therefore he cannot perfectly judge of the character of another man's deeds, nor can he accurately decide upon their goodness or badness, for there are many actions which are outwardly good and inwardly bad and therefore are displeasing to God. Accordingly the good or evil of a man's action is evident in perfection to God alone, because He, being aware of what is within as well as what is without a man, sees all his thoughts and desires as they really are, and knows all his deeds and conduct. Accordingly it is written:—

O1 LORD, thou hast searched me, and known me.
Thou knowest my downsitting and mine uprising,
Thou understandest my thought afar off.
Thou searchest out my path and my lying down,
And art acquainted with all my ways.
For there is not a word in my tongue,
But, lo, O LORD, thou knowest it altogether.

1 Ps. cxxxix. 1-4.  

And for the very reason that God, the holy and the just, is all-knowing, He knows not only the outward but also the inward nature of man's actions and will recompense them. And just because every external act first takes shape internally that is, in thought and wish, so it is that man in his heart commits numberless sins that do not in any measure become outwardly manifest, since either he has no opportunity and power to commit them openly and bring his desire to accomplishment, or he is afraid of this world's disgrace and loss and punishment, and for that reason does not display those evil desires and vain thoughts which he has in his heart, and thus refrains from putting them in practice. Hence no one is aware of those faults and sins, except God, who knoweth what is secret. And though these wishes and thoughts do not become manifest, yet, being sins in God's sight, like each evil deed, they are deserving of punishment: for between these two things there is only this difference, that man does the outward deeds with the limbs and members of the body, and the inward deeds—that is to say, wishes and thoughts—in his heart, through the instrumentality of his spirit. And though on this account these latter actions do not become visible to men, yet they, too, like the outward acts, are the man's own doings. Therefore a man's evil desires and vain thoughts, whether they become manifest in action or remain hidden, are sin in God's sight,