I'm reading through Matthew lately.  Ever notice how such simple concepts can take you completely by surprise?  I think the shock is actually half "What a neato idea" & half "You dolt - it took you this long?"  Jesus was blunt.  He didn't practice the art of sugar coating.  If you were in the wrong, He let you know.  Perhaps it is His sincerity in His bluntness that makes His sincerity in His compassion so believable.  If He will be so painfully honest about condemning you, it stands to reason He is also honest about His desire to redeem you.  The people who followed Him did not doubt His love for them, perhaps because they never had reason to doubt His words.