Springfield, USA - Families with more than 10 children are becoming the norm among a group of traditionalist US Christians. The so-called Quiverfull families believe they are carrying out God's work, and providing a new generation of moral leaders. The BBC's religious affairs correspondent Robert Pigott went to Illinois to meet some of them.
The way Psalm 127 talks about children has an almost military sound.
It describes them as "an inheritance, and arrows in the hands of a mighty warrior," adding, "happy is he whose quiver is full of them".
Many Quiverfull families do indeed sense looming battles for Christians, and often see their children as potential future leaders in fighting them.
Rev James McDonald has 10 children, aged between four and 26 - an extraordinary fertility motivated by obedience to the Bible.
"We believe that they are blessings… to be raised up in the worship of the Lord and they will be used by him in whatever way God will call them, to fulfil the Great Commission which we find in Matthew Chapter 28," he said.
The "Great Commission" - the duty to spread the Christian message throughout the world - is among a number of challenges Mr McDonald sees facing his family.
Among others, he cites divorce, adultery, abortion and internet pornography.
"The societal ills that we have, the challenges we have... we have rampant disease and bankrupt health systems because we don't know the truth of the Bible. But as these truths are lived out in the lives of God's people, society changes," he said.
Declining congregations
The McDonalds are being joined in the battle by a growing number of very large traditionalist Christian families equally committed to promoting Biblical values.
When the Sanfords came to lunch, it was to celebrate the departure overseas of Garrison, one of their 13 offspring, to serve with the US marines.
They say his Christian example has already led his comrades to behave better.
When Garrison and the rest of his family drew up in a 15-seat minibus to be greeted by the McDonalds, a crowd was instantly created on the gravel outside the McDonalds' house.
The Sanfords - who have no television at home, and who all join in the household chores - give an impression of moderation and discipline.
The siblings address their father as "sir", and their esprit de corps is enhanced by wearing similar clothes.
Quiverfull families tend to believe in male headship - the principle, also derived from the Bible, that men should lead households.
Feminists are perhaps the fiercest critics of the budding Quiverfull movement.
They accuse it of trying to undo the equality and freedom won for women over decades of struggle, and claim that the idea of automatic male leadership is anachronistic.
But Robert Sanford sees his approach to family life both as authentically Christian, and as the best training for children to take on what he sees as the moral decay afflicting American society.
"I think we should as Christians lead in that way, and we can teach that character and teach those morals," he said.
"To me the Bible is the best way of doing it. In my estimation, the Bible is the only way of doing it."
At Providence Church in Morton, Illinois, the Sanfords occupy two full pews, uniformly dressed in black shirts and beige trousers or skirts.
There are several very large families here, their 15-seat mini-vans scattered across the car park.
James McDonald, the pastor here, uses the service to baptise a boy, immersing him bodily in a bath-type pool set up on the raised floor at the front of the church.
The boy's parents watch and wrap a towel around him as he emerges.
Pastor McDonald looks out on a sea of children, mostly conservatively dressed, many of the girls with their hair covered.
But, given what he sees in other churches, he is not complacent about their numbers.
"In denomination after denomination their children are leaving in mass exodus, and this is a major major problem especially when most families only have two or three children," he said.
"Who's going to fill those pews in the next generation?"
There is a wider concern too that going beyond the United States to traditionally Christian regions such as Europe, Christianity seems to be dying out.
'Race suicide'
Simply filling the world with white Christians is not what motivated either the Sanfords or the McDonalds - for them having large families was a matter of faith.
The Sanfords have adopted children from around the world.
But many of the traditionalist Christians who make up the Quiverfull movement are perplexed by the low birth rate of their co-religionists.
There is no overt talk about the need to boost white populations but, according to authors who have studied the movement, there is an underlying worry about "race suicide".
Allan Carlson favours larger families of any background, even though he says he is, as he puts it, a "radical secularist".
Dr Carlson heads the Howard Center for Family, Religion and Society in Rockford, Illinois, a research group arguing that a shortage of children threatens the world economy.
He says many Quiverfull families want to undermine what they regard as a "contraceptive mentality" in the West.
"The historic Christian view, Protestant and Catholic, prior to 1930, was that both contraception and abortion were incompatible with Christian faith," he said.
"We're starting to see some sense among conservative Protestants in America that that was the correct view, and I think that plays into the movement for larger families."
Many of those families are linked into the wider population of traditionalist Christians by the home-schooling movement, by which it is estimated that more than two million American children are taught at home.
They share concerns particularly about "life" issues - such as abortion and stem-cell research, but about promoting other traditionalist Christian values too, in areas such as marriage.
Mr Carlson - who advocates a reversal of the industrial revolution and a return to home-based businesses centred on the family - says there is a strategic motivation behind the Quiverfull movement.
"There is a sense in which these intentionally created large families are seeing themselves as the… foundation of a counter-culture, which could grow, and should grow," he said.
This counter-culture is still small, in the thousands or tens of thousands perhaps, but it does seem to be emerging as a determined force.
Quiverfull families insist that the government cannot fix America's problems, but that their children could.