As much as I respect Albert Mohler, president of the Southern Baptist Theological Seminary, and admire his stand on Calvinism despite the fact that so many of his peers are dead-set against it, I have to admit that I think that he can be a legalist. I'm sure some of my Moderate Baptist brethren would say, "Duh, we could have told you that," but I am not concerned with all of those debates. No, the matter that I have in mind is the forcing of parenthood upon married couples. Dr. Mohler recently appeared on CNN to push his legalistic views on the nation. Read his own account of it at http://www.albertmohler.com/blog_read.php?id=416. He has also talked about this sort of thing in the past. A few articles can be found here and here.
For Dr. Mohler, intentional childlessness on the part of married couples is sin. Why? Because children are a gift from God. We are commanded to receive gifts from God with joy. But does this mean that we must demand this gift? Does the word "gift" imply that we must demand it? It does not. For some gifts, we are commanded to seek after them, such as the grace of salvation. But the Bible does not command that all couples in all generations until the end of the world are to procreate. The Bible says that a good wife is far more precious than jewels (Proverbs 31:10), but Paul says that it is better not to marry (1 Corinthians 7:8). Being as Dr. Mohler is an avid defender of the expositional style of preaching (for which I am grateful), it is surprising to see that this is all the Scripture that Mohler uses to defend his case, and he doesn't even exegete it.
What about the command to Adam and Eve and Noah to go forth and multiply? Does that apply to everybody? Obviously not, and on this Dr. Mohler would agree. Since Paul writes of the preference for the single life over married life, it is obvious that God does not intend everybody to marry. And it is also very obvious from God's law that only married people should procreate. So no, as Dr. Mohler would agree with me, the multiplication mandate given to Adam is not for everybody, just for those who marry. How are we to infer this from the text? I believe that it is reading the Bible through the lenses of tradition. God is speaking to Adam and Eve. And though I agree that the command probably includes future generations, we cannot dogmatically say so. He was speaking to specific people, and the command He gave them had a specific purpose. Christ was to come in to the world so that Adam and Eve could be saved. Therefore, they had to procreate so that Christ would come. Same for Noah, of course. But does this mean that everybody should procreate? I don't think that there is enough evidence in the Bible to dogmatically affirm that to choose childlessness is to sin.
Personally, I think that the multiplication mandate was for the old covenant only. It finds its new covenant fulfillment in the Great Commission. And besides, how full does the earth have to be until the mandate is fulfilled? How are we to judge? I could imagine a paedobaptist being keen on this mandatory procreation idea, because that would mean filling the earth up with more Christians that way. But for a credobaptist to take this position is just silly. The main priority for Christian couples is to help each other in bring the Gospel to the lost. Children are secondary.
But ultimately, what does Scripture say is the purpose of marriage? We find it in Genesis 2:18-25. God decided to give Adam a "fit helper." It does not say that Adam needed fit helpers. It does not say that Adam needed someone who would help him create even more helpers. Adam just needed one. And in verse 24 we find a Biblical command for marriage: "Therefore a man shall leave his father and his mother and hold fast to his wife and they shall become one flesh." That is all you will find regarding dogmatic commands for all married couples.
Now don't get me wrong; I am not saying that people should not have children. I am just saying that it is not a sin if they choose not to. If it was, then we would have it listed in Leviticus with some sort of punishment involved for violating it. There is no such law. We should not impose upon believers what God does not impose. That is the very definition of legalism.
I am certain that the matter of procreation falls under the same category as Paul's instructions concerning marriage. Just as it is better to not marry but it is certainly not wrong to marry, so it may be better to have children, but it is not wrong to not have children by choice. Speaking of this particular passage in 1 Corinthians, after Paul gives his instructions to single people, he has specific instructions for married people (7:10-11). Not one word is said about procreation. In the preceding paragraphs, Paul speaks of marriage as a means to avoid fornication. So there he speaks explicitly about marriage and sex, but he does not talk about procreation.
If you want to believe that you should have children lest you sin, fine. It is just like abstaining from food offered to idols. That is your perogative, and your duty if you really believe it. But you cannot force a concept that is nowhere found in Scripture upon other believers. That is extra-biblical, which is legalism.
I know that this idea of mandatory procreation is popular among Reformed folk, and I might even be in the minority. But I feel convinced that such a concept cannot be supported by Scripture either explicity or by necessary inference. I think the only thing that can be inferred from Scripture is that children are a blessing and yahoo for those who get them, and that specific people such as Adam, Eve, Noah, and the ancestors of Christ and the Jewish people, were to multiply. But that is all that can be deduced from Scripture. To add more than that to the consciences of men is to bind them with legalism.