...and do not give the devil a foothold. (NIV) Eph 4:27
The flesh is just comparable to a toddler. If allowed to have its own way, it would satisfy its id to the point of inadvertent self-destruction. So it needs to be controlled by a more disciplined system which is the human mind. The concept of self-control appears here: the moment the mind denies the heart the fulfillment of its sweet but unprofitable desires. This is hard work.
Today, the Bible is showing us a way of overcoming temptation which is easier than exercising self-control. That way is to avoid situations that make our environment suitable for temptations. Often before we are faced with a temptation, there are numerous signs that warn us of an imminent danger. Usually, we choose to ignore these signs. We choose to ignore the fireballs from the creature until we are finally faced with the dragon itself. It is at that point we seek escape routes when it is actually too late. Let us run away from situations that facilitate temptations rather than running towards temptations and wanting to overcome them. Else, we may always fall into them (1 Cor. 6:18).
Imagine fraternizing with a whore in her bedroom and finally being offered an opportunity to bed her for free. Success in turning down such an offer for religious reasons using self-control is simply too much of hard work. It would have been easier by never entering her room. It would have been even easier to have not entered the brothel in the first place. Still, it is easier to have not used the road that passes in front of the brothel.
When you offer the devil a foothold, he can stand against you. Let us offer him none so he will have no place to stand around us.