In verse 4, Satan slyly convinces Eve that God has lied to them by withholding from them the ability to become "like God, knowing good and evil." God was being unfair, he argues, keeping them from their potential. The passage suggests that, after hearing this, Eve did not hesitate one bit in making her decision. She took the bait without even flinching and ignorantly promoted the interests of Satan by giving the forbidden fruit to her husband. In effect, she signed on to advance Satan's objective—to derail God's plan to create mankind in His spiritual image.
Satan's tack has been the same ever since, even though he must realize that, due to Christ's death and resurrection, he will ultimately lose (Revelation 20:10). While he still has time, he will try to make as many people as he can fail to reach their incredible human potential. He will do whatever is in his power—whatever God allows him to do—to convince them that his way is superior to God's.
For those that have been called by God in this lifetime, we have far more at stake here. If Satan can succeed in deceiving us to advocate for him more and more, he greatly increases our chances of being subject to the second death, the eternal death in the Lake of Fire (Revelation 20:14-15).
Peter warns us of the dangers that Satan poses to God's people: "Be sober, be vigilant; because your adversary the devil walks about like a roaring lion, seeking whom he may devour" (I Peter 5:8). According to the Exegetical Dictionary of the New Testament, "sober" (Greek nepho) is a verb found in the New Testament only in the figurative sense, implying "sober watchfulness." In addition, "vigilant" (Greek gregoreuo) means "to keep awake, i.e., watch (literally or figuratively)."
Combining "sober" and "vigilant" paints an interesting word-picture for us. When a person is heavily intoxicated, he wants nothing more than to sleep it off, so it is impossible for the sleeping drunkard to be vigilant about anything. The message for us is that we must be attentive to our physical and spiritual condition so that we do not become spiritually intoxicated. This type of person is exactly the kind whom Satan seeks. If we enter this state, then we make ourselves a prime target to be devoured by the "roaring lion."
Should a Christian Play Devil's Advocate?