Luke 13:14
He said to them, Make every effort to enter through the narrow door, because many, I tell you, will try to enter and will not be able to — the narrow door communicates that the kingdom's entrance is not wide enough to accommodate the unreformed and uncommitted. The effort required is not earning salvation but the decisive, wholehearted response that the kingdom demands. The many who try and cannot enter are those who assumed entry without making the necessary response.