It does not matter how great the exploits that we do for God are, it doesn't matter how long that we have been walking with God, it doesn't matter how much of a knowledge we have of the Word of God, we still must TAKE HEED that we do not fall. If we ever needed to be on gaurd and watchful it is now. This is the same Greek word that is used to describe the two violent demoniacs of Gadera. This suggests that the condition of the end times will be energized by demons. It will be a time when it will be diffucult to maintain one's own spiritual equilibruim.
Spiritual drowsiness is always a very real threat at the midnight hour.
Subtle dangers will present themselves to Christians just before the coming of the Lord. Therefore we ought to give the more earnest heed to the things which we have heard, lest at any time we should let them slip. When we begin to neglect the things that bring spiritual strength we begin to drift. It is not enough to just learn what is good, but we must continue in it, and persevere in it to the very end. Paul was telling Timothy that if he would continue in what he had been taught from the Word of God he would be sucessful.