A few words from Martin Luther related to family and marriage life, taken from his Table Talk.
It is no wonder that Satan is an enemy to Christ, his people and kingdom, and sets himself against him and his word, with all his power and cunning. T’is an old hate and grudge between them, which began in Paradise: for they are, by nature and kind, of contrary minds and dispositions. The devil smells Christ many hundred miles off; he hears at Constantinople and at Rome, what we at Wittenberg teach and preach against his kingdom; he feels also what hurt and damage he sustains thereby; there rages and swells he so horribly.
But what is more to be wondered at is, that we, who are of one kind and nature, and, through, the bond of love, knit so fast together that each ought to love the other as himself, should have, at times, such envy, hate, wrath, discord and revenge, that one is ready to kill the other. For who is nearer allied to a man, than his wife; to the son, than his father; to the daughter, than her mother; to the brother, than his sister, etc.? yet, it is most commonly found, that discord and strife are among them. 
If the emperor proceed to war upon us, he intends either to destroy our preaching, and our religion, or to invade and confound public policy and economy, that is to say, the temporal government and administration. In either case, t’is no longer as emperor of the Romans, legally elected we are to regard him but as a tyrant; t’is, therefore, futile to ask whether we may combat for the upright, pure doctrine, and for religion; t’is for us a law and a duty to combat for wife, for children, servants, and subjects; we are bound to defend them against maleficent power…But the temporal and civil person is subject to the temporal rights and laws, and tied to obedience; it must maintain and defend itself, and what belongs to it, as the laws command. For example, if, in my presence, some wretch should attempt to do violence to my wife or my daughter, then I should lay aside my spiritual person, and recur to the temporal; I should slay him on the spot, or call for help. For, in the absence of the magistrates, and when they cannot be had, the law of the nation is in force, and permits us to call upon our neighbor for help; Christ and the Gospel do not abolish temporal rights and ordinances, but confirm them.