"gift" or "valued possession." Children normally receive an inheritance from their parents. Inheritance goes from parents to children. This passage refers to children as the inheritance of their parents.
Arrows are very important to a warrior because they protect him in battle. Children are spoken of as if they are a warrior's arrow. AT: "Having many children will help to protect you" (See: [[rc://en/ta/man/translate/figs-simile]])
A quiver is a container for arrows. Having many children is spoken of as if the children were arrows in a quiver. AT: "a home full of children" or "many children" (See: [[rc://en/ta/man/translate/figs-metaphor]])