Eph 4 In your anger do not sin" : Do not let the sun go down while you are still angry, and do not give the devil a foothold.
  Ps 4 4In your anger do not sin; when you are on your beds, search your hearts and be silent. Selah Offer right sacrifices and trust in the LORD .

"In your anger do not sin" in the NT comes from the parallel passage in Psalms. In the incarnation Christ had to suffer death in order to be the atoning sacrifice taught in Psalm 4 "offer right sacrifices". The OT zabah is lit. offer the "animal that has been slain." Tearing the animal into pieces is a metaphor God applying the curses upon Jesus. God uses this metaphor when He upbraids Israel for focusing on the physical traits of the animal. Ps50  "Consider this, you who forget God, or I will tear you to pieces, with none to rescue:" If we offer the sacrifice without the pronouncement of death to the wicked God is not pleased. The sacrifice was more than an atonement. It was a consecration of the covenant promises. The Psalmist is teaching that they recited the law with the right attitude displayed in the sacrifice.16  But to the wicked, God says: "What right have you to recite my laws
or take my covenant on your lips? They did not offer the sacrifices in the spirit of the curses. When we approach God in praise, sorrow, petition and complaint it must be in a holistic way. We must speak with the law, covenants, curses, statutes, promises and decrees.

God has given us a way to express our anger through the pronouncements of the curses in order to consecrate our anger. The Psalmist is comparing the violent act of slaying the animal with the heat of human anger. Christ not only satisfied the law by His active and passive obedience, death and resurrection, but He had to endure the violence in the punishment for our sin. This is why the Psalmist teaches that sin is the act of violent rebellion in redefining the legal pronouncements of the king.God deals with the violence by pronouncing the death to the offender. We cannot avoid the consequences of abuse as we relate to sinners. So we have the virus of personal anger that must be quarantined in the pronouncement of the curse. If God loves us with action then He must respond to sin by mending the abuse we experience. So God has spoken  the curses in order for us to experience His defense so that we are healed. If we do not use the legal defense in the curses then we let the anger linger and it hardens our hearts.