We are all called to live a Purpose Driven Life. When a person doesn’t invest in their purpose, they live a frustrated life. When you know and understand your calling, it is easier to walk worthy of it.
For example, a Doctor can only live to the fullest of his potential if he knows he was called to be a Doctor. He/she will invest in what it takes to become good at what he/she does. When you believe who you were called to be, you will surely be the best you can be.
In regards to salvation, unfortunately, many christians don’t preach the gospel, not because they are disadvantaged but because they don’t really believe it, that what the Bible says is actually true. They dont believe that Joshua actually stopped the sun, that Jesus raised the dead, that He actually died and rose again for them. If they knew and believed, Christ would be their new fantacy, their new addiction, they would be the best man/ woman of God, God called them to be