What does Psalm 127:5 mean?

This continues the thought begun in the prior verse (Psalm 127:4). The father—or, by extension, any parent—of many children is blessed or happy. Children are always a blessing from God. They are not a punishment, or a problem, or a burden. At the same time, neither are children a product, meant to be mass-produced simply for the sake of making more.

Earlier, children were compared to the arrows of a warrior. The children a person has in their youth one day become their defense and support in old age. The point is not that God demands or commands that people have a "quiverfull" of offspring. That is, we are not obligated to have as many children as possible. More children, especially in an era where family was a person's only form of security in his or her later years, would have meant more blessing.

Another advantage to children is the support of family in disputes with others. The gates of a city were where business and judgment would be conducted (Deuteronomy 21:19–21; Ruth 4; Amos 5:12; Proverbs 1:21; 31:23). A person dealing with personal conflicts can expect help from family. When he faces his accusers, he will not be left abandoned or shamed. His children will support him in the dispute. They will serve as his character witnesses. In a more practical sense, in the ancient world, the more sons an Old Testament community had, the less likely an enemy would be to attack the city by entering its gate.

Although Psalm 127 honors the family with biological children, it must be pointed out that parents of adopted children are equally blessed by the Lord. So are those who pour into the lives of children who are not theirs, at all. Whether our children, grandchildren, nieces, nephews, friend's children, or other children with whom we come into contact, we all have opportunity to promote the truth of the value of a child's life and help them grow in the Lord. We do this by our words, through our actions, and in our prayers. Jesus said, "Whoever receives one such child in my name receives me, but whoever causes one of these little ones who believes in me to sin, it would be better for him to have a great millstone fastened around his neck and to be drowned in the depth of the sea" (Matthew 18:5–6). Having a ministry to children is both a great privilege and an awesome responsibility. That looks different for those who have children of their own, who adopt, or who simply interact with the children of others. But it's a solemn duty, all the same.