Gerhard and Walther

However, those are unworthy guests at this heavenly Meal who do not examine themselves; who do not judge themselves; do not remember the death of Christ, nor proclaim it, nor discern His body; i.e., who without true repentance, without true faith, and without the sincere intention to better themselves from now on, who live in impenitence, self-assurance, godlessness, and unreconciled with their neighbor; who do not from God’s Law confess their sin, nor bear any contrition or sorrow over their sin; who do not believe that Christ’s body and blood are truly present; who do not believe these words, given and shed for you; who do not thank Christ for this His great love, etc.—Johann Gerhard, Schola Pietatis I:115.

It is clear, therefore, that whoever does not inquire of God about his choice, depending on his own wisdom or following impure motives, takes a spouse, but does not find her. He may make his choice on the basis of fleeting beauty, uncertain riches, quickly dwindling honor, or the hope of good days or a voluptuous life.—C. F. W. Walther (sermon on Proverbs 18:22), God Grant It!, p. 133.