'Vigor' in the Bible

“Reuben, you are my firstborn;My might, the beginning of my strength and vigor,Preeminent in dignity and preeminent in power [that should have been your birthright].

“Indeed, how could the strength of their hands profit me?Vigor had perished from them.

We grope for a wall like the blind,We grope like those who have no eyes.We stumble at midday as in the twilight;Among those who are healthy we are like dead men.