“Marriage Is For Making Children….Disciples of Jesus.  There is a double meaning in that title that I hope will help you remember the point.  Marriage is for making children – that is, procreation.  Having babies.  This is not the main meaning of marriage.  But it is an important one and a biblical one.  But then I add the words “disciples of Jesus.”  Marriage is for making children into disciples of Jesus.  Here the focus shifts.  This purpose of marriage is not merely to add more bodies to the planet.  The point is to increase the number of followers of Jesus on the planet. 

The effect of saying it this way is that couples who cannot conceive because of infertility can still aim to make children followers of Jesus.  God’s purpose in making marriage the place to have children was never merely to fill the earth with people, but to fill the earth with worshippers of the true God.  One way for a marriage to fill the earth with worshippers of the true God is to procreate and bring the children up in the Lord.  But that’s not the only way.  When the focus of marriage becomes “Make children disciples of Jesus,” the meaning of marriage in relation to children is not mainly “Make them,” but “Make them disciples.”  And the latter can happen even where the former doesn’t.”

Copied from pages 138-139 of John Piper’s book “This Momentary Marriage.”