Biblical references telling us we should be angry Overheard on a Christian Radio station this morning:  


  We all know that Jesus said if we are angry without cause, we are in
  danger of hellfire, and that the Bible tells us to be slow to anger.
  But did you know that there are situations in which the Bible says we
  are supposed to be angry?


Unfortunately, I couldn't listen to the program being advertised,  so I'll ask it here.  Where, in Scripture are we told to be angry, and about what is it OK to be angry?  What is the "cause" that is acceptable if we aren't supposed to be angry "without cause".  Please include Scripture references.  If applicable, links or comments from official/recognized teachings would be a good addition, particularly if the Scripture reference could be interpreted multiple ways.
Scripture gives several examples of righteous anger.  This is anger towards sin, or injustice.

Most of these show God being angry.  Since God is without sin, it follows that if we in agreement with God, we are safe being angry with the same things He is angry with.  Examples:

God the Father is angry with sin

All verses KJV


  Psalms 7:11 God judgeth the righteous, and God is angry with the wicked every day.
  
  1 Kings 11:9,10 And the LORD was angry with Solomon, because his heart had turned away from the LORD, the God of Israel, who had
  appeared to him twice and had commanded him concerning this thing,
  that he should not go after other gods. But he did not keep what the
  LORD commanded.
  
  2 Kings 17:18 Therefore the LORD was very angry with Israel and removed them out of his sight. None was left but the tribe of Judah
  only.


Likewise, Jesus displayed anger at unrighteousness.


  Mark 3:4,5 And he [Jesus] said to them, “Is it lawful on the Sabbath to do good or to do harm, to save life or to kill?” But they
  were silent. And he looked around at them with anger, grieved at their
  hardness of heart, and said to the man, “Stretch out your hand.” He
  stretched it out, and his hand was restored.
  
  John 2:13-16 The Passover of the Jews was at hand, and Jesus went up to Jerusalem.  In the temple he found those who were selling oxen
  and sheep and pigeons, and the money-changers sitting there. And
  making a whip of cords, he drove them all out of the temple, with the
  sheep and oxen. And he poured out the coins of the money-changers and
  overturned their tables. And he told those who sold the pigeons, “Take
  these things away; do not make my Father’s house a house of trade.”


One other passage speaks of being angry, and the context seems to say that it's O.K. to be angry, but not to let your anger provoke you to sin, and is followed immediately by a warning to not let your anger consume you - and to forgive as Christ forgives us.

From Ephesians 4


  26 Be ye angry, and sin not: let not the sun go down upon your wrath:
  
  27 Neither give place to the devil.
  
  28 Let him that stole steal no more: but rather let him labour,
  working with his hands the thing which is good, that he may have to
  give to him that needeth.
  
  29 Let no corrupt communication proceed out of your mouth, but that
  which is good to the use of edifying, that it may minister grace unto
  the hearers.
  
  30 And grieve not the holy Spirit of God, whereby ye are sealed unto
  the day of redemption.
  
  31 Let all bitterness, and wrath, and anger, and clamour, and evil
  speaking, be put away from you, with all malice:
  
  32 And be ye kind one to another, tenderhearted, forgiving one
  another, even as God for Christ's sake hath forgiven you.