וְקוֹיֵ֤ יְהוָה֙ יַחֲלִ֣יפוּ כֹ֔חַ יַעֲל֥וּ אֵ֖בֶר כַּנְּשָׁרִ֑ים יָר֙וּצוּ֙ וְלֹ֣א יִיגָ֔עוּ יֵלְכ֖וּ וְלֹ֥א יִיעָֽפוּ׃ (פ)
But they that wait for the LORD shall renew their strength; They shall mount up with wings as eagles; They shall run, and not be weary; They shall walk, and not faint.
Ibn Ezra on Isaiah
יחליפו כח Shall renew their strength. Before one power is exhausted, the other is prepared for them by the Almighty. Comp. if it be cut down, (יחליף) it will sprout again (Job. 14:7). In Arabic this word has a similar meaning.64خَلَفَ Successor alicujus fuit; خَلِيفَةٌ Khalif. (Freytag, Lex. Arab. Lat.)
Ibn Ezra on Isaiah
אבר Wing. Comp. Ps. 55:7.—The sense of the whole verse seems to be this: The Israelites that trusted in the Almighty will be strengthened by Him, and He will bring them back to Jerusalem; the Babylonians, who are now mighty, will be weakened.