ISB ~ Ephesians 4 v26

Be angry but do not sin:Not all anger is sinful or harmful. Righteous indignation is an appropriate response to offenses committed against God (Ps 119:53; Mk 3:5). In the case of personal insults, we should strive for reconciliation with the offender before the day’s end. Otherwise the rift will begin to widen as resentment, bitterness, and hatred consume us.

• Paul is alluding to Ps 4:4, where the Psalmist calls us to examine our hearts in silence before going to bed.