2 Corinthians 13:5

Examine yourselves to see whether you are in the faith; test yourselves. Do you not realize that Christ Jesus is in you? unless, of course, you fail the test? 

The Bible tells us that all we have to do to qualify for salvation is to believe in Jesus. Seems simple enough but I can honestly say that it is far easier said than done. Truly believing in Jesus is more than saying to yourself, "Ok, I believe." You may tell yourself this but is it really in your heart? Do you belive with all your heart, mind, body and soul? True belief affects a change in lifestyle. For instance, we can say we believe but pride and returning to sin can cause us to be disqualified and cut off from GOD's love. Through faith, our lives change and we distance ourselves as best we can from our former lives of sin. This is not automatic but takes serious effort but we persevere because we want to please the Lord in whom we believe. Constant sefl examination can help to determine whether we are growing in our faith for nearing disqualification due to lapses is our quest.

True belief is more than just stating that we accept Christ. We must stay the course lest we fall back into our former lives.