Isaiah 40:31

וְקוֹיֵ יְהוָה יַחֲלִיפוּ כֹחַ יַעֲלוּ אֵבֶר כַּנְּשָׁרִים יָרוּצוּ וְלֹא יִיגָעוּ יֵלְכוּ וְלֹא יִיעָפוּ׃

31 But those who wait for the LORD will renew their strength and they will rise up on wings like eagles. They will run and not be weary; they will walk and not become faint.

וְקוֹיֵ יְהוָה יַחֲלִיפוּ כֹחַ But those who wait for the LORD will renew their strength, Another "Those who..." participle is found in וְקוֹיֵ, qal plural construct from קָוָה "wait eagerly." There isn't always the "eager" sense to this word, but it's fairly common and probably to be discerned from the context. An Mp note claims that the phrase וְקוֹיֵ יְהוָה is a hapax legomenon, but there is a sub loco notation among the Mm reference numbers because the phrase actually occurs again in Psalm 37:9. יַחֲלִיפוּ is a hifil imperfect from חָלַף, which in the qal means "pass away" or "pass through," but in the hifil can mean "sprout" (of grass) or "renew, change."

יַעֲלוּ אֵבֶר כַּנְּשָׁרִים and they will rise up on wings like eagles. The noun אֵבֶר means "wing," and even has a verbal form meaning "soar up" or "wing" in a verbal sense in Job 39:26. The נֶשֶׁר is any soaring raptor like a vulture, hawk or eagle. In context, the high-flying quality is the emphasis, and so "eagle" is probably the best choice in our culture (the image of a vulture calls up another set of thoughts entirely). The Mp note is simple enough to understand: אֵבֶר occurs twice. The other place is Psalm 55:7, "Oh, that I had wings like a dove!"

יָרוּצוּ וְלֹא יִיגָעוּ They will run and not be weary; The ayin-waw רוּץ "run" retains all its radicals here in the qal imperfect. In other stems like the polel the tsade reduplicates and the waw assimilates. The combination וְלֹא יִיגָעוּ is joined by the conjunctive accent munach, as happened in verse 28. The effect is for the negative to be joined inseparably to the verb as if they were a single thought (this is almost always the effect of munach).

יֵלְכוּ וְלֹא יִיעָפוּ they will walk and not become faint. יִיעָפוּ is in pause; the only other time this qal imperfect form occurs (Jer. 2:24) it not in pause, but the vowels are identical in this doubly weak verb (pe-yod, double-ayin). This phrase is simply the logical parallel thought to the preceding. The verse ends with a setumah paragraph marker, which also serves to close out the chapter.