Charles H. Spurgeon on Psalms 103:5

Thy youth is renewed like the eagle's. It is an ancient fable that the eagle is able to renew his youth when very old, and poetical allusion is made to it in this Psalm; but this idea is doubtless founded in reality on the great longevity of the bird, and its power, in common with other birds, of moulting its plumage periodically, and so increasing its strength and activity. Hugh Mac Millan. {1} {1} We might have filled much of our space with the fables from the rabbis and the fathers in reference to eagles; but they are too absurd, and ought never to be repeated. We hope, therefore, that the reader will excuse if not commend the omission.