In my assessment for church planting with the SBC back in 2000 I was told by one of the assessors that I had an anger problem. I argued that I did not. A lot. Half way through the conversation let's just say my anger decided to join the conversation. I spent many years being angry--from my youth to well into adulthood. Before my conversion it could be violent. After my conversion it could be explosive. By the grace of God I have found freedom from its grip on me, but it took years of growing in grace. One of the most influential books to help me in this area was Matthew Henry's Quest for Meekness and Quietness of Spirit (paperback, Kindle). I have read it several times and walk other men through it as well. In fact this morning I met with a brother from Redeemer to discuss another section of the book as we are reading it together. We are angry men by nature, but are becoming quiet men by grace. I cannot recommend Quest for Meekness highly enough for those who desire to learn humility and maintain a quiet heart.
Meekness teaches us prudently to govern our own anger whenever any thing occurs that is provoking. As it is the work of temperance to moderate our natural appetites in things that are pleasing to sense, so it is the work of meekness to moderate our natural passions against those things that are displeasing to sense, and to guide and govern our resentments. Anger in the soul is like mettle in a horse, good if it be well managed. Now meekness is the bridle, as wisdom is the hand that gives law to it, puts it into the right way, and keeps it in an even, steady, and regular pace; reducing it when it turns aside, preserving it in a due decorum, and restraining it and giving it check when at any time it grows headstrong and outrageous, and threatens mischief to ourselves or others. It must thus be held in, like the horse and mule, with bit and bridle, lest it break the hedge, run over those that stand in its way, or throw the rider himself headlong. It is true of anger, as we say of fire, that it is a good servant but a "bad master;" it is good on the hearth, but bad in the hangings. Meekness keeps it in its place, sets banks to this sea, and says, Hitherto thou shalt come, and no further; here shall thy proud waves be stayed.