Five Stages of Spiritual Development
Based Upon Experience
Those who have thoroughly practiced the 12 steps (Confession, self-examination, repentance, restitution, service, prayer, meditation, etc.) and have had a spiritual awakening will likely confirm the truth with this process. Those who have not experienced the above process, just can't know.
Do a concordance search of the Bible using the words "Those who." Read page 85 in the book Alcoholics Anonymous. Get a sponsor or mentor and go through all the 12 steps thoroughly as the book describes them and learn.
Our own inward condition is a result upon how well we live by spiritual principles.