Mrk. 7:20-23 ... "That which proceeds out of the man, that is what defiles the man. For from within out of the heart of man, proceed the evil thoughts and fornications, thefts, murders, adulteries, deeds of coveting and wickedness, as well as deceit, sensuality, envy, slander, pride and foolishness. All these evil things proceed from within and defile the man."
In warfare the commander of any army is always focused upon the strategy of the opposing commander, trying to determine what he intends to do next so that he might parry his movements and attack him where he is weakest or unsuspecting. At the same time, the commander must be aware of elements with-in his own army, or the country he is defending, that are actually covert enemies. Often called a "fifth column," this internal enemy uses opportunity to commit acts of sabotage and insurrection that greatly weaken the frontline army. In some cases, such activity behind an army brings about its defeat. In I Samuel 29, the Philistine army set out to attack Israel. At that time, David with a band of about 600 men, all outcasts from Israel, were in the service of Achish, one of the Philistine lords. When the other lords noticed it, they became angry and demanded that Achish send these Israelite retainers back, "lest in the battle he (David) become an adversary to us." So, David and his men were expelled and went back to Philistia.
In the warfare of each Christian against the force of evil, he must be aware of the very real likelihood of any enemy within him that weakens him and makes him vulnerable to "the schemes (strategies) of the devil," (Eph. 6:11). How does the devil, or the spirit of evil, find a place within a Christian who is trying to serve the Lord and even be one of His warriors against evil? By infiltration! Due to weakness, lack of attention, distraction, social influence, and especially the desire (lust) for what is not best, (see Jas. 1:14-16), evil penetrates our minds and hearts and begins its work. If a Christian is not aware of it, the fruits of evil germinate and begin to grow. What are these fruits? Jesus names several of them in the Mark 7 passage quoted above: evil thoughts, fornication, theft, murder, adultery, covetous deeds, deceit, sensu-ality, envy, slander, pride and foolishness." Sin is a rottenness within a person, which, if not seen and resisted, will spread. One sin will lead to another, and that to another, spreading the rottenness until the Christian loses his identity and deserts the army of Christ to serve Satan.
In the New Testament we are often warned of this ever present danger and told how to deal with it. First, we are told in I Pet. 5:8-9 to "Be of sober spirit, be on the alert, your adversary, the devil, prowls about like a roaring lion, seeking someone to devour, but resist him, firm in your faith." The aperture through which evil enters one's life is temptation, and our natural desire for what seems "good ... that ... (is) a delight to the eyes ... that (is) desirabe to make one wise," (Gen. 3:6), is often an open invitation for sin to enter. Anyone who does not stay conscious of this threat and just takes life experience as it comes, will admit sin without realizing it. In the Parable of the Sower, Jesus said that some of His disciples are like seed that was "sown among the thorns ... who hear the word, (but) the worry of the world, and the deceitfulness of riches choke the word, and it becomes unfruitful," (Mat. 13:22). The admittance of sin precludes the development of good fruit and produces an ever greater abundance of the fruit of evil listed above. Every Christian must be very aware of the enemy within and oppose it strongly.
