What does Numbers 24:21 mean?

And he looked on the Kenite, and took up his parable, and said, Strong is thy dwelling-place, And thy nest is set in the rock.

And he looked on the Kenites, and took up his parable, and said, Strong is thy dwellingplace, and thou puttest thy nest in a rock.

And he looked on the Kenite, and took up his parable, and said, Strong is thy dwelling-place, And thy nest is set in the rock.

And looking on the Kenites he went on with his story and said, Strong is your living-place, and your secret place is safe in the rock.

And he seeth the Kenite, and taketh up his simile, and saith: `Enduring <FI>is<Fi> thy dwelling, And setting in a rock thy nest,

He saw also the Cinite: and took up his parable, and said: Thy habitation indeed is strong: but though thou build thy nest in a rock,

And he saw the Kenites, and took up his parable, and said, Firm is thy dwelling-place, and thy nest fixed in the rock;