How does the eagle's bird renew its youth, and what is the meaning of that verse in general?
According to the Jewish understanding, the eagle is a long-lived bird of prey, which under certain conditions can reach the age of 70 years. But when the eagle reaches the age of 40, he must make an exceedingly difficult decision, because his nails have become long and are no longer so flexible and cannot easily grab the prey. Also, the long and sharp beak has become very curved, so that it cannot cut its prey, while the wings have become heavy because the feathers have become very thick and stick to the chest, so that the eagle has difficulty flying.
Then the eagle has two options left. Either to die or to go through a painful replacement process that lasts 150 days. This process requires the eagle to soar to the top of a mountain and stay there for the time being. There the eagle strikes the rock with its beak until it breaks off its beak. Then he waits for his new beak to grow, and then he breaks his claws with his beak. When his new claws grow then he plucks his old feathers. After five months, the eagle regenerates and can live another 40 years.
In one sentence, comparing spiritual renewal with an eagle, the prophet of God speaks of a painful transformation of the soul. Namely, every Christian is called to overcome in himself that old man who is enslaved by deceptive desires that deceive and deceive him, and to put on Christ. That painful process of renewal is repentance, it is breaking and breaking the accumulated passions in the soul. But this transformation does not take place without struggle and without restraint until the soul is adorned with the necessary virtues, like an eagle with new feathers and soars to great heights. Repentance also requires courage, but we are comforted by the fact that God loves brave souls.