Adam Clarke on 1 Timothy 3:5

For if a man know not - Method is a matter of great importance in all the affairs of life. It is a true saying, He that does little with his head must do much with his hands; and even then the business is not half done for want of method. Now, he who has a proper method of doing business will show it in every affair of life, even the least. He who has a disorderly family has no government of that family; he probably has none because he has no method, no plan, of presiding. It was natural for the apostle to say, If a man know not how to rule his own house, how shall he take care of the Church of God? Look at a man's domestic arrangements; if they be not good, he should not be trusted with any branch of government, whether ecclesiastical or civil.