Charles H. Spurgeon on Psalms 103:5

Thy youth is renewed like the eagle's. This renovation of his youth may be understood three ways. First, as to his natural state, or bodily strength. Secondly, as to his civil state, or worldly successes, as to his honour and kingly-renown. Thirdly, as to his spiritual state, or the heightening of his gifts, graces, and comforts. It is probable David had found a declension in all these, and at last, through the goodness of God and his blessing upon him, the renewing of them all from that oldness to a youthfulness again, like that of eagles. Joseph Garyl.