An analogy how to become a real Christian - The Pharisee and the Tax Collector (Luke 18:9-14)

Jesus tells this parable (metaphorical analogy with a spiritual meaning) to illustrate how sinners can receive eternal life. Sinners cannot justify (save) themselves by relying on their own righteousness (good works). Although justification occurs instantaneously, God does require sinners to humble themselves, acknowledge their own sinfulness and ask God for forgiveness. Only God can justify people.
It is impossible for man to save himself but with God all things are possible (Matthew 19:26).