What does the Bible say about entering through the narrow door?

In Luke 13:24, Christ instructs us to 'make every effort to enter through the narrow door,' indicating that salvation is a serious endeavor. This narrow door symbolizes the exclusive way to eternal life, which is through faith in Christ alone. Many may seek to enter, relying on their own merits, but without a true understanding of their sinfulness and need for Christ, they will find themselves unable to enter. The focus should be not on the number of those who will be saved but rather on our own personal assurance of being among them.