Matthew 7:13-14
Enter by the narrow gate; for wide is the gate and broad is the way that leads to destruction, and there are many who go in by it.  Because narrow is the gate and difficult is the way which leads to life, and there are few who find it.
 
Matthew 7:21-23
Not everyone who says to Me, "Lord, Lord," shall enter the kingdom of heaven, but he who does the will of My Father in heaven.  Many will say to Me in that day, "Lord, Lord have we not prophesied in Your name, cast out demons in Your name, and dont many wonders in Your name?" And then I will declare to them, "I never knew you; depart from Me, you who practice lawlessness.
 
In reference to these verses, Pastor John MacArthur said...
vs 13-14   Both the narrow gate and the wide gate are assumed to provide the entrance to God's kingdom.  Two ways are offered to people.  The narrow gate is by faith, ony through Christ, constricted and precise.  It represents true salvation in God's way that leads to life eternal.  The wide gate includes all religions of works and self-righteousness, with no singe way, but it leads to hell, not heaven.
 
vs 21  The barrenness of this sort of faith demonstrates its real charater - the faith that says but does not do is really unbelief.  Jesus was not suggesting that works are meritorious for salvation, but that true fatih will not fail to produce the fruit of good works.  This is precisely the point of James 1:22-25, James 2:26.
 
vs 22  Note that far from being totally devoid of works of any kind, these people were claiming to have done some remarkable signs and wonders.  In fact, their whole confidencew was in these works - further proof that these works, spectacular as they might have appeared, could not have been authentic.  No one so bereft of genuine faith could prossibly produce true good works.  A bad tree cannot bear good fruit (vs 18).