In the absolute sense, the purpose of marriage is, as everywhere, God's glory. Then, besides the good that husband and wife are to have from each other in the estate of marriage (Ge 2:18; Eph 5:25-29,31; Col 3:19), its purpose is the raising of the next generation in the discipline and admonition of the Lord (Eph 6:4; Col 3:21; Dt 6:7,20, Pr 19:18). The chief obligation of parents toward children consists in this, and children in turn owe parents obedience (Ex 20:12; Eph 6:1; Col 3:20).
The Christian home is a miniature of the church within the church (ecclesiola in ecclesia), whose priest is the head of the home. Therefore divine service must not be lacking (Dt 6:7; Ge 18:19; 2 Co 12:14). Obviously the scope of the household's divine service cannot include that which belongs in the realm of the preaching office (Predigamt). That consideration excludes the administration of the sacraments and preaching, insofar as it is public, i.e., addressed to persons other than the members of the household.

Adolf Hoenecke, Evangelical Lutheran Dogmatics, vol. 4, trans. Joel Fredrich, Paul Prange, and Bill Tackmier (Milwaukee: Northwestern Publishing House, 1999), 229-30.

The Word of God is the strengthening and the nourishment for our faith-life in all the conflicts and troubles of this present existence. Therefore we will have our own personal devotional life where we read, mark, learn, and inwardly digest the Word. Our household will have its family altar so that our children realize that Jesus and His cross are not just for Sunday. Here our family will gather around the Word to be nourished daily by the Savior so that we can face the difficulties of day-to-day living.

Gaylin R. Schmeling, Bread of Life from Heaven: The Theology of the Means of Grace, the Public Ministry, and Church Fellowship (Mankato, MN: Bethany Lutheran Theological Seminary, 2009), 32.

Therefore God has also most richly blessed this estate [marriage] above all others, and, in addition, has bestowed on it and wrapped up in it everything in the world, to the end that this estate might be well and richly provided for. Married life is therefore no jest or presumption; but it is an excellent thing and a matter of divine seriousness. For it is of the highest importance to Him that persons be raised who may serve the world and promote the knowledge of God, godly living, and all virtues, to fight against wickedness and the devil.

Large Catechism, Sixth Commandment, 208

All whom we call masters are in the place of parents and must derive their power and authority to govern from them. Hence also they are all called fathers in the Scriptures, as those who in their government perform the functions of a father, and should have a paternal heart toward their subordinates. As also from antiquity the Romans and other nations called the masters and mistresses of the household patres- et matres- familiae, that is, housefathers and housemothers. So also they called their national rulers and overlords patres patriae, that is, fathers of the entire country, for a great shame to us who would be Christians that we do not likewise call them so, or, at least, do not esteem and honor them as such.

Large Catechism, Fourth Commandment, 142.