Isaiah 40:31

But they that wait upon the Lord,.... As children on their parents, to do them honour, to obey their commands, and receive food and blessings from them; as servants on their masters, to know their pleasure, do their work, and have their wages; as clients on their patrons, to have advice of them, put their cause into their hands, and know how it goes; and as beggars at the door, who knock and wait, tell their case and wait, meet with repulses, yet keep their place, and continue waiting: such an act supposes a knowledge and reverence of God, confidence in him, attendance on him, not with the body only, in public and private, but with the soul also, and with some degree of constancy, and with patience and quietness: the Lord is to be waited upon for the manifestations of himself, who sometimes hides himself, but is to be waited for, since he has his set time to show himself again, and his presence is worth waiting for; also for the performance of his promises, which may be expected from his perfections, the nature of the promises, and their being in Christ; likewise for answers of prayer, and for the fresh discoveries of pardoning grace and mercy; and as Old Testament saints waited for the first coming of Christ, so New Testament saints for his second coming, and for eternal glory and happiness: and such "shall renew their strength"; which is to be understood of spiritual! strength in the heart, and of the graces of the Spirit there: it supposes strength received already, which natural men have not, but converted men have; and yet they want more, and more they shall have; to assist them in the performance of duty, to enable them to resist Satan and his temptations, and the corruptions of nature, and to cause them to endure afflictions and persecutions patiently, and to persevere unto the end:

they shall mount up with wings as eagles; swiftly and strongly; it is expressive of the motion of the affections heavenwards towards God and Christ, and things above; of the entrance of faith and hope within the veil, and of the exercise of these graces on Christ, who is now at the right hand of God; of the expectation of glory and happiness in heaven hereafter, and of present support under afflictions, the Lord bearing them as on eagles' wings; see Psalms 103:5 g:

they shall run, and not be weary; in the way of God's commandments; which shows great affection for them, haste to obey them, delight and pleasure, cheerfulness and alacrity, therein, so as to be without weariness:

and they shall, walk, and not faint: in the ways of God, in the name of the Lord, or in Christ, as they have received him; leaning on him, trusting in him, continuing to do so, till they receive the end of their faith, the salvation of their souls; and so shall not sink under their burdens, nor give out till they enjoy it; different persons, though all of them believers, may be here intended; particularly Christians under the Gospel dispensation, tried and exercised by many enemies; some shall soar aloft, and dwell on high; others, though they cannot rise and "fly" so swiftly and strongly, yet shall "run" without weariness; and others, though they can neither fly nor run, yet shall "walk" without fainting.

g The Jews have a notion, that for ten years the eagle ascends very high in the firmament of heaven, and approaching near to the heat of the sun, it falls into the sea, through the vehemence of the heat; and then it casts its feathers, and is renewed again, and its feathers grow, and it returns to the days of its youth; and so every ten years to a hundred; and in the hundredth year it ascends according to its custom, and falls into the sea, and dies. So Ben Melech from Saadiab Gaon.