To be born again is a concept that cannot be easily explained naturally, but can be compared to certain natural phenomena, such as birth. But to experience it is much simpler than to understand it.
We know that God is able to keep us until the end, but this is a call to re-commit ourselves to him as we run the race set before us, working out our salvation with fear and trembling.
Righteousness can only be obtained by believing that Jesus Christ has paid for one’s sins by his death and given us new life by his resurrection. Nothing else will make a man righteous before God.