Oh, how our lives would be transformed and our perspective on being fruitful and multiplying would be enlightened if only we were to live out the meaning of Luther's words below:
"Every man is created and born for the sake of others." WA 21, 346
The hearts and minds of the married man and wife (whether contracepting or not) say for much of their married life: "No, we do not want this gift of marital bliss to result in the creation and birth of another human being right now - we want it to serve only our pleasure - we have the right to want what we do in the privacy of our own bedroom to serve only our gratification and to nurture only our own one-on-one relationship - we only want this gift of marital bliss to result in the life of another person when we believe it best serves our purposes and desires as a couple - only if and when WE want a baby."
In our sinful hearts we must all confess that we do not want our entire lives to serve others, and we do not want to create and nurture more lives to serve others unless it fits into our own selfish plans for our own fulfillment. I confess this myself, even though my wife and I employ absolutely no means of contraception, including NFP. Sin is in the heart, and my heart is full of it.
If you are a preacher of mercy, do not preach an imaginary but the true mercy. If the mercy is true, you must therefore bear the true, not an imaginary sin. God does not save those who are only imaginary sinners. Be a sinner, and let your sins be strong, but let your trust in Christ be stronger, and rejoice in Christ who is the victor over sin, death, and the world. [Luther's supposed "sin boldly" letter to Melanchthon]