Jesaja 40:30

Faith is all that is needed to ensure a participation in the strength (עצמה after the form חכמה), which He so richly bestows and so powerfully enhances. "And youths grow faint and weary, and young men suffer a fall. But they who wait for Jehovah gain fresh strength; lift up their wings like eagles; run, and are not weary; go forward, and do not faint." Even youths, even young men in the early bloom of their morning of life (bachūrı̄m, youths, from בּחר, related to בּכר, בּגר), succumb to the effects of the loss of sustenance or over-exertion (both futures are defective, the first letter being dropped), and any outward obstacle is sufficient to cause them to fall (נכשׁל with inf. abs. kal, which retains what has been stated for contemplation, according to Ges. 131, 3, Anm. 2). In Isa 40:30 the verb stands first, Isa 40:30 being like a concessive clause in relation to Isa 40:31. "Even though this may happen, it is different with those who wait for Jehovah," i.e., those who believe in Him; for the Old Testament applies to faith a number of synonyms denoting trust, hope, and longing, and thus describes it according to its inmost nature, as fiducia and as hope, directed to the manifestation and completion of that which is hoped for. The Vav cop. introduces the antithesis, as in Isa 40:8. החליף, to cause one to pursue, or new to take the place of the old (Lat. recentare). The expression וגו יעלוּ is supposed by early translators, after the Sept., Targ. Jer., and Saad., to refer to the moulting of the eagle and the growth of the new feathers, which we meet with in Psa 103:5 (cf., Mic 1:16) as a figurative representation of the renewal of youth through grace. But Hitzig correctly observes that העלה is never met with as the causative of the kal used in Isa 5:6, and moreover tha…