The psalm opens with a statement: unless the Lord builds the house, those who build it labor in vain. The word house can mean a building, a family or a dynasty. Unless the Lord watches over the city, the watchman stays awake in vain. Human effort is still needed, but it is not enough by itself.
Verse 2 brings it to daily life: it is vain to rise early, to go late to rest and to eat the bread of anxious toil, for God gives sleep to his beloved. The text does not praise laziness but rebukes the anxiety that believes everything depends on oneself.
Verses 3 to 5 change the picture: children are a heritage from the Lord and the fruit of the womb is a reward. Like arrows in the hand of a warrior are the children of one's youth. Blessed is the man who fills his quiver with them, for he will not be put to shame when he speaks with his enemies in the gate, that is, in the place where public and legal matters were handled.