The Christians `marry like all the rest of the people and they beget children but they don`t throw away their newborn babies.`. Meaning that the Christians come at the communion of marriage but their marriage is blessed by God.
Saint Ignatius Theophorus writes to saint Policarpus: `The men and the women who marry must make their marriage with the consent of the bishop so that their union be with God`s blessing` according to the view of the Church, `not according to their desires. Meaning that it is not made because I like you and you like me, neglecting the fact that the other one belongs to another religion etc. Everything to be done for honoring God. 
Therefore the Christian marries but his marriage is with God`s blessing. This means wedding, to receive God`s blessing. The Christian doesn`t consent to the civil wedding alone, because he considers it debauchery. And that`s what it is, because it is not blessed. Saint Paul, the Apostle says:
And you my brother, when it comes to such an important thing from your life as marriage, you marry without blessing, without God?
My beloved, beware! It is not something malicious what I am going to say. If your son – may this not happen – marries only with a civil wedding, do not go to his wedding, because it is not a right one. If a relative or a friend marries with a civil wedding, do not go! Tell him or her that it is not something right! Do not offend, do not do anything disgraceful, only tell them that they don`t do what`s right. Beware! Do not bring them any gifts, because by your presence, by your visit or by your gift you consent to something which is not agreed by God, something which is illegal. Do what saint Paul, the Apostle urged the Corinthians to do with a certain Christian who had sinned, not to speak with him, to make him be ashamed and come to his senses.. Show your discontent and do this not only today or tomorrow or for ten days but until he will correct his behavior.
 The Letter to Diognet, Chapter V, 6, p. 340.
 Saint Ignatius Teophorus to Policarpus, Chapter V, 2, PSB, Vol. I. IBMBOR Publishing 1979, p. 188.
 I Corinthians 10, 31.
 I Corinthians 5, 1-11.
Excerpt from the book THE CHRISTIANS IN THE WORLD (Hieromonk Athanasios Mitilineos)