In describing the way of salvation, Jesus said that: (1) Entry was through the "strait gate", (2) His commandment was that all who seek it should "strive to enter in", (3) The solemn warning He gave was that "many shall seek and shall not be able".
The path of the strait gate is the only way to eternal life; to peace with God; to pardon and forgiveness. The gate is strait, and the road is difficult, especially to to all who love their sin; for all who will not repent; to all who love this world and to all who want a life of ease. The way of Calvary's cross, through Jesus Christ, and through Him alone is the only way. We will not be saved by good works, or anything else that we have 'done'. We must come individually to Jesus. He bids all to come, even the vilest sinner will be granted entrance if he repents and believes.
We must strive to enter in, we must be earnest in our desire for salvation and heaven. What else matters? Their can be no room, or place for laziness in our attention to these vital things.
Many, we are told, will 'seek', but for some they will not be able to find. One day it will be too late, the day of grace will be over, the gate will be closed, the opportunity lost. Do you know where you will spend eternity, will your realisation that you need to go through the strait gate be in time?