Many people have had life experiences that lead them to a closer walk with the Lord. Moses had his encounter with the burning bush....King David as a small boy had a Prophet choose him out of all his brothers to receive the anointing of the Holy Spirit.
These life experiences changed the course of their lives forever. Some people read their bibles and the Truth speaks to their hearts. They open themselves up to the Holy Spirit and He helps them come to understanding.
Just a mustard seed amount of faith is all it takes to have one's eyes opened. No one can read the bible and understand it until the Holy Spirit gives them the ability. It's all about us being moved by the Spirit to take step by step in our walk to find the Way the Truth and the Life.
I even have my own life experience that changed me forever and it involved times in my life that humbled me. Allowed me to see my life as it really was. It also allowed to see where my strength actually came from.
One thing I know. It does not come from man, or man's knowledge...it comes from the One that knows all things and has a great love for us to come to Him in our need. To lay it all down at His feet and say yes, I accept all that you have done in the name of Jesus the Christ. Allowing the blood of Christ to wash the stain of sin away and renewing our spirit with the Spirit of God.