Physiologus: On the Natures of Twelve Animals

...food. And thus the curvature of the old beak falls away and is diminished, and so the eagle itself grows young again and is able to eat.

¶ It should be noted regarding the first verse where it says, "They say it is..." original: "Esse ferunt..." etc., that some say the eagle is the first among birds because it was created first. Others say it is the first not in that way, but because it is more noble and flies higher than other birds.

And the human, with sins that are from his mother's origin, a reference to Original Sin
Like the eagle, is renewed by water;
He transcends the clouds and feels the heat of the sun
By despising the world with its empty vanities.
He becomes new in Christ, immersed in the living flood;
From above, that pious living fountain flows.
He wears down the crooked mouth through words praying to Christ—
Who is Christ? The Rock original: "petra", as the Apostle St. Paul affirms this.
For the new bread is sweeter than all honey;
The bread—that is Christ—becomes food without end.

¶ Here the author consequently provides the allegory or the allegorical sense allegorical sense: the deeper spiritual meaning hidden behind the literal description, saying that by the eagle, any sinner is understood. And just as old age is deformed and despised, so the sinner is despised and deformed in the eyes of God. And rightly, just as old age weighs down the eagle, so sins weigh down the human conscience. Whence Augustine St. Augustine of Hippo, a hugely influential early Christian philosopher says: "Among all the tribulations of the soul, there is no greater tribulation than the conscience of a sinner." Therefore, just as the sinner is like the aged eagle, when he performs penance, he is renewed like the eagle. Whence the Psalmist says: "Bless the Lord, O my soul" original: "Benedicat anima mea dominum" etc. and it follows, "And your youth shall be renewed like the eagle's." Psalm 103:5

In this way, the penitent human, by the wings of desire, transcends the clouds; that is, those things which are above—namely heavenly things—he tastes and contemplates, despising the world with all its vanities original: "pompis"; refers to the empty shows and distractions of worldly life. This is according to the counsel of the Apostle St. Paul, in Colossians 3:2 saying: "Set your mind on things that are above, and not on things that are on the earth." Then he feels the heat of the sun, that is, the grace and mercy of Christ, who is the true Sun of Justice Sun of Justice: a common medieval title for Christ, symbolizing his role in illuminating the soul and burning away sin. And He burns away whatever of evil desire may be in him and illuminates his clouded eyes.

And just as the aged eagle, falling from on high, plunges itself into a continually flowing fountain and thus renews itself, so the human falls from on high—that is, from pride—and plunges himself into the fountain of tears through penance. Whence Isidore Isidore of Seville, a 7th-century scholar known for his encyclopedias says: "The tears of a penitent are accounted before God as a second baptism" and...