Satan is looking for just a little door into your life. It doesn't have to be a big one, but Satan is looking for a door so he can come in and eventually get you into sin.
It is possible to stay pure and glorify God in your body. It may be hard at times, especially without the Word of God to point the way. But God has given us His Word. And He is not unjust; since He said to glorify Him in your body; therefore, it is certainly possible.
But I [Paul] keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, that I myself should be a castaway.
(1 Cor. 9:27)
Notice Paul said, "I keep under my body." It's not God's job (or anyone else's job) to keep your body in line - it's your job. The word "keep" implies that you're going to have to do it over and over again, on a continual basis, not just once or twice.

Therefore, glorifying God in our body is something we need to continually pay attention to. We need to make sure we're doing the right thing all the time, so we don't get into a position where Satan can come in and cause havoc in our lives.

You see, Satan is looking for just a little door into your life. It doesn't have to be a big one. You may be an on-fire, Bible-believing Christian who knows all about glorifying God in your body.

You may be being blessed immeasurably in your Christian walk, but Satan is looking for a door into your life so he can come in and eventually get you into sin. He wants to gradually get you into sin so that you wake up one day and say, "What happened? How did I get in this mess?"

You left the door open.

Find Out What Doors To Keep Closed
We need to know what to do to make sure Satan can't get even a foothold, much less a stronghold, into our lives. It's easier to keep him out of our lives than it is to get him out after we've already let him in.

Sometimes, people let Satan into their life, and their sin "finds them out" (Num. 32:23), especially in the case of a single girl getting pregnant. Then everyone's saying, "Look what she did." What people don't realize is, the sin in her life started months or perhaps even years before the pregnancy.

She might have been a Christian who was living right for God, but then she let some things slip. Over time, she got a little deeper into some things that were wrong - she started thinking wrong, looking at the wrong things, hanging around the wrong people, and so forth - and things got worse and worse.

However, when everyone sees the girl pregnant, they have the impression that her sin just happened "out of the blue." But that's not how it works.

Sin is a progression. "Little sins" lead to "big sins"; it's a process. Satan doesn't usually just walk up to a saved, sanctified Christian and say, "Hey, let's go to Vegas and gamble away twenty thousand dollars." No, he's more subtle than that.

All he really has to do is get you on the path to sin. Then he knows that he'll get you eventually.

Source: God's Plan for the Single Saint by Keith Butler, II.
Excerpt permission granted by Word of Faith Publishing