Rev. Larry Peters' has an excellent post on anger (glad to know I'm not the only one noticing this danger) here after meditating on Paul's words, "Be angry and do not sin" (Ephesians 4:26).
I connected the verse just before that to the 8th Commandment in my sermon yesterday. Found this quote explaining Ephesians 4:25 by Rev. Armin Panning in CPH's People's Bible Commentary for Galatians/Ephesians: “Dishonesty is especially damaging when it occurs among believers, ‘for we are all members of one body.’ To deceive a fellow Christian is really to harm ourselves, because just as in the human body all the members work together for the common good, so it is also in the church. Being dishonest with another Christian is like shooting ourselves in the foot” (pg. 191).
Oh, and nothing to do with the Epistle, just a great illustration from Gerhard, by way of Pr. Weedon here. Going to have to file that one away for a sermon sometime.