Humility & Faith In Jesus As Our Door of Salvation
Luke 13:24 (ESV) … “Strive to enter through the narrow door. For many, I tell you, will seek to enter and will not be able.”
Jesus represented the way of salvation as “the narrow door.” This image suggests the moral posture of the person who would strive to enter the kingdom. I. H. Marshall notes that “the imagery is akin to that of a camel passing through the needle’s eye, and suggests the difficulty of facing up to the demands of Jesus in self-denial.” The passage to Heaven is not through the great portal of a palace, but a narrow, low door through which one must humbly squeeze. And after entering, the road remains narrow, as Jesus explained when he preached at another time: “Enter through the narrow gate. For wide is the gate and broad is the road that leads to destruction, and many enter through it. But small is the gate and narrow the road that leads to life, and only a few find it” (Matthew 7:13, 14).
Few people are willing to assume the humble posture and to shed what is necessary to get through the gate, and few are willing to tread the narrow road.
The Lord’s call to “make every effort to enter” (v. 24) or “strive to enter” (rsv) is the Greek word agonizomai, from which we get our word agonize. This is the kind of moral effort necessary to enter the kingdom. “We are not saved by effort, but we shall not believe without effort.”
In light of what is at stake (Heaven or Hell) and in light of the finality of eternity, we cannot strive too much to get through the narrow door. It must be sought with all that we are. We must agonize (strive in faith) over being sure to enter the kingdom of God.
 Hughes, R. K. (1998). Luke: that you may know the truth (pp. 97–98). Wheaton, IL: Crossway Books.