The Holy Scriptures challenge the believer in Jesus Christ to continually examine himself to determine if he is still in "the faith". This self-examination is essential for proper Christian growth and development in the principles of the kingdom of God. Likewise failure to observe this statute opens the door to self-deception and error in living. We must learn to judge ourselves first.
Matthew 7:13-14 King James Version (KJV)
13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.