“They who wait for the Lord (hope in the Lord) will gain new strength (will renew their strength); they will mount up with wings (sprout wings) like eagles (soar as with eagles wings), they will run and not get tired (not grow weary), they will walk and not become weary (walk and not grow faint).”
Isaiah 40:31 (Combined New American Standard Bible and The New American Bible, Saint Joseph Edition)
Below are some QUOTED INSIGHTS from my Bible research as I explored the above verse in various commentaries.
“[Shall renew their strength] The Hebrew word commonly means to change, to alter; and then to revive, to renew, to cause to flourish again, as, e.g., a tree that has decayed and fallen down (see Isa 9:10; and Job 14:7 – 9 Be sure to check out this excellent comparison!). Here it is evidently used in the sense of renewing, or causing to revive; to increase, and to restore that which is decayed. It means that the people of God who trust in him shall become strong in faith; able to contend with their spiritual foes, to gain the victory over their sins, and to discharge aright the duties, and to meet aright the trials of life. God gives them strength, if they seek him in the way of his appointment—a promise which has been verified in the experience of his people in every age [and at every season of human life].
“[They shall mount up with wings as eagles] One translation is 'They shall put forth fresh feathers like the moulting eagle;' and in the note on this passage, 'It has been a common and popular opinion that the eagle lives and retains his vigor to a great age; and that, beyond the common lot of other birds, he molts in his old age, and renews his feathers, and with them his youth.' He supposes that the passage in Ps. 103:5, 'So that thy youth is renewed like the eagles,' refers to this fact. This was a common and popular opinion among the ancient biblical writers. The opinion was, that at stated times the eagle plunged itself in the sea and cast off its old feathers, and that new feathers started forth, and that thus it lived often to the hundredth year. In accordance with this opinion, the Septuagint renders this passage, 'They shall put forth fresh feathers [pterofueesousin] like eagles.' Vulgate, Assument pennas sicut aquiloe.
“The literal meaning of the Hebrew is, 'they shall ascend on wings as eagles,' or 'they shall lift up the wings as eagles;' and the image is derived from the fact that the eagle rises on the strongest, most vigorous wings of any bird, and ascends apparently further toward the sun. The figure, therefore, denotes strength and vigor of purpose; strong and manly piety; an elevation above the world; communion with God, and a nearness to his throne—as the eagle ascends toward the sun.
“[They shall run and not be weary] This passage, also, is but another mode of expressing the same idea—that they who trust in God would be vigorous, elevated, unwearied; that he would sustain and uphold them; and that in his service they would never faint. This was at first designed to be applied to the Jews in captivity in Babylon to induce them to put their trust in God. But it is as true now as it was at that time. It has been found in the experience of thousands and tens of thousands, that by waiting on the Lord the heart has been invigorated; the faith has been confirmed; and the affections have been raised above the world. Strength has been given to bear trial without complaining, to engage in arduous duty without fainting, to pursue the perilous and toilsome journey of life without exhaustion, and to rise above the world in hope and peace on the bed of death.
(from Barnes' Notes, Electronic Database. Copyright (c) 1997 by Biblesoft)
Leona’s comment: Catholic teaching emphasizes the need for detachment from sin and negative lifestyle (molting our tired, worn, old feathers) and attachment to God’s eternal truths and a holy lifestyle (renewing our spiritual strength.) Many biblical passages affirm the need for this double-edged action: “Put off the old man, put on the new nature; put aside the works of darkness, walk in the light, etc.” Practical lists of the “put offs” and “put ons” (attachments and detachments) are given in Scripture, so we are not left in doubt of what God wants us to do.
In our advanced years, we have accumulated a great deal that needs to be put off by virtue of how long we have lived. We have a lot of molting to do! But the rewards are wonderful: Youth renewed! Soaring closer to God! New strength and vigor for the rest of the way in the toilsome journey of life!