It is rare to succeed without effort. A student must study for good grades and the probability of success increases only when an entrepreneur strives.
It is the same with ones life in Christ. In the Bible is a "Parable of Ten Virgins" in which we read of 10 virgins who waited for their bridegroom with their lamps but only the prudent five virgins who had prepared enough oil for their lamps could welcome the bridegroom. The foolish five virgins fell asleep without having prepared oil and were not invited to the wedding (Matthew 25).
The Parable tells us that merely being a "Christian" does not warrant ones salvation. Each of us must always make sure whether or not the lamps of faith, hope, and love are brightly alight.

~ from Rev. Dr. Jaerock Lees column series "The Way" in The Hankyoreh daily