The oldest angels are the youngest. The longer men live in fellowship with Christ, the stronger do they grow. And though our lives, whether we are Christians or no, are necessarily subject to the common laws of mortality, we may carry all that is worth preserving of the earliest stages into the latest; and when grey hairs are upon us, and we are living next door to our graves, we may still have the enthusiasm, the energy, and above all, the boundless hopefulness that made the gladness and the spring of our long-buried youth. 'They shall still bring forth fruit in old age.' 'The youths shall faint and be weary, but they that wait upon the Lord shall renew their strength.'
There is one more point to touch, and then I have done, and that is the manner in which this immortal strength is exercised. The latter clauses of my text give us, so to speak, three forms of motion. 'They shall mount up with wings as eagles.' Some good commentators find in this a parallel to the words in the 103rd Psalm, 'My youth is renewed like the eagle's,' and propose to translate it in this fashion, 'They shall cast their plumage like the eagle.' But it seems much more in accordance with the context and the language to adopt substantially the reading of our English version here, or to make the slight change, 'They shall lift up their wings as the eagle,' implying, of course, the steady upward flight towards the light of heaven.
So, then, there are three forms of unwearied strength lying ready for you, young men and women, to take for your very own if you like: strength to soar, strength to run, strength to walk.
There is strength to soar. Old men generally shed their wings, and can only manage to crawl. They have done with romance. Enthusiasms are dead. Sometimes they cynically smile at their own past selves and their dreams. And it is a bad sign when an old man does that. But for the most part they are content, unless they have got Christ in their hearts, to keep along the low levels, and their soaring days are done. But if you and I have Jesus Christ for the life of our spirits, as certainly as fire sends its shooting tongues upwards, so certainly shall we rise above the sorrows and sins and cares of this 'dim spot which men call earth,' and find an ampler field for buoyant motion high up in communion with God. Strength to soar means the gracious power of bringing all heaven into our grasp, and setting our affections on things above. As the night falls, and joys become fewer and life sterner, and hopes become rarer and more doubtful, it is something to feel that, however straitened may be the ground below, there is plenty of room above, and that, though we are strangers upon earth, we can lift our thoughts yonder. If there be darkness here, still we can 'outsoar the shadow of our night,' and live close to the sun in fellowship with God. Dear brethren, life on earth were too wretched unless it were possible to 'mount up with wings as eagles.'
Again, you may have strength to run--that is to say, there is power waiting for you for all the great crises of your lives which call for special, though it may be brief, exertion. Such crises will come to each of you, in sorrow, work, difficulty, hard conflicts. Moments will be sprung upon you without warning, in which you will feel that years hang on the issue of an instant. Great tasks will be clashed down before you unexpectedly which will demand the gathering together of all your power. And there is only one way to be ready for such times as these, and that is to live waiting on the Lord, near Christ, with Him in your hearts, and then nothing will come that will be too hard for you. However rough the road, and however severe the struggle, and however swift the pace, you will be able to keep it up. Though it may be with panting lungs and a throbbing heart, and dim eyes and quivering muscles, yet if you wait on the Lord you will run and not be weary. You will be masters of the crises.