In explaining the actuations of His disciples of neglecting some of the Jewish ritual washings, Jesus Christ explained that “there is nothing outside a man which by going into Him can defile Him; but the things which come out of a man are what defile Him” (Mark 7:15).
The people could not understand what Jesus meant, but it would be explained later on.
The Jews made a lot of fuss over the type of food they could eat. Certain items where forbidden because they were considered as “unclean,” not in the hygienic or physical sphere, but in the religious one. Such was the old dispensation.
But Christ had come to bring a new dispensation, and in this one, more emphasis was to be laid on the inner dispositions. Through Christ’s words, no type of food could really be considered “unclean” from the religious point of view. Instead, we have to be watchful over the things that came out “from within, out of the heart” (Mark 7:21).
The transgression of the law of God, which is what constitutes sin, really starts from our inner being. After all, the transgression has to be “voluntary,” it is something that is willed. And willing is a supremely interior act. That is why Saint Augustine describes sin as a “turning away from God” and a “turning toward creatures.”
Unfortunately, some people with desires to improve and to be followers of Christ forget the importance of the inner dispositions. They readily admit that it would be wrong to kill, to steal, to commit adultery, etc.; but they don’t give any importance to the envy, the hatred or the lust, which are the real roots of those external sins.
It is, therefore, important in the spiritual life to give value to what are called “internal” sins, such as bad thoughts, desires, imaginations and the like.
Although internal sins may not have as serious a consequence as when it is also externalized, in a certain sense, internal sins can be a more dangerous enemy, just as a spy or a hidden enemy can be more dangerous than one who is out in the open.
It is harder for us to detect an internal sin than an external one. A person might harm another out of anger, and because he sees the external injury, he may come to his senses and be sorry for that sin.
But if a person merely harbors thoughts of resentment, he may not even notice it, thinking himself to be the most charitable of men.
It can be amusing at times to see people claim that they bear no hatred for anyone, yet mention a certain name and you can see them flush with anger or resentment.
I am not saying that it would, therefore, be better to execute an internal sin in the name of “being more spontaneous and natural.” All I mean is that, if we truly want to put the Christian way of life into practice, we should be attentive to our internal dispositions and carry on the ascetical combat in that sphere.