It is important to realize that when a Christian is saved, God does not leave them alone. Philippians 1:6-7 gives the guarantee that what God has begun, He will certainly finish. 1 Corinthians 6:11 does not accredit one's self for the new life but the new life is by the Spirit of God. The Holy Spirit works not only as a Comforter but also as a Rebuker of sin. Because of the fact that the Christian is still not yet perfect it is very normal for them to get absorbed into themselves. It is probably because before they were saved, they were told that the answer is within them. Sometimes, they tend to lean back towards that tendency to lean on themselves. Even if they may not live like devils but it cannot be denied that backsliding can happen for a certain period of time.
The problem can also be seen in Joshua's conquest of Gibeon. In Joshua 9, we read the whole encounter with Gibeon. Joshua was deceived by the Gibeonites because he did not consult God at all concerning that decision. Christians can also fall into that serious mistake of making the wrong decisions because they failed to ask God to guide their footsteps. As Proverbs 3:5 says that one must trust in the LORD with all one's heart to get a straight path. The question is how often do you ask God to guide your footsteps?