A Warning from Jesus If Jesus really loves everyone, why does Jesus show no mercy on the non believers? 

Matthew 7:21-23: 

Not everyone who calls me their Lord will get into the kingdom of heaven.  
Only the ones who obey my Father in heaven will get in.
On the day of judgment many will call me their Lord.
They will say, "We preached in your name, and in your name we force out demons and
worked many miracles."  But I will tell them, "I will have nothing to do with you!
Get out of my sight, you evil people!"


Since this question is on hold due to opinion base, I'll attempt to form it more not opinion base.  Matthew 7:21-23 has always disturbed me.  Why does this passage warn and state the response from Jesus to the individuals who confront him with mercy?  The quotes could be left out and the passage could just be:

Not everyone who calls me their Lord will get into the kingdom of heaven.
Only the ones who obey my Father in heaven will get in.
On the day of judgment many will call me their Lord.


Is this due to translation from the old testament to the new testament?
The best explanation I heard on this passage goes like this : "Depart from me all those who professed to be my followers, yet lived your lives as if I had never given you commands to live by". In other words, all those who never tried to be holy like Jesus.  And, by the way, ALL sins are mortal unless they are forgiven by Jesus. And He can forgive EVERY sin.