21 “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. 22 On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’ 23 And then will I declare to them, ‘I never knew you; depart from me, you workers of lawlessness.’
Let me explain why these words scare me.
The people being asked to depart are the people who are saying "Lord" and recounting all the things they have done in the name of JESUS. How, is it possible to live your life in the name of Jesus, but not actually walk with him and know him?
Many within the Christian faith forget the main tenet of our faith. "For it is by grace you have been saved, through faith--and this is not from yourselves, it is the gift of God" - Ephesians 2:8. Good works do NOT provide salvation from sin. Only grace. However, the grace that brings us salvation, saves us so that we CAN do good works.
The scripture in Matthew above came right on the heels of Jesus talking about us knowing other believers by the fruit that comes out of lives. So someone can verbally say Lord (which means master) but not say Lord with their actual way of life. It's so important for us as Christians to live our lives not just going through the motions, but constantly resting in the grace of God. We are to live every moment, not for our own ambitions, fulfillment, wealth; but, every moment should be lived for the glory of God and the furtherance of his gospel and kingdom. That's true living. Walk with him and you'll never have to fear those words.