unless

Psalm 127
1 Unless the LORD builds a house,
  the work of the builders is wasted.
Unless the LORD protects a city,
  guarding it with sentries will do no good.
2 It is useless for you to work so hard
  from early morning until late at night,
anxiously working for food to eat;
  for God gives rest to his loved ones.

3 Children are a gift from the LORD;
  they are a reward from him.
4 Children born to a young man
  are like arrows in a warrior's hands.
5 How joyful is the man whose quiver is full of them!
  He will not be put to shame when he confronts his accusers at the city gates.