III. Again, I see here a life which has discovered the secret of perpetual youth. 'I,' says the old man--'am as strong this day as I was in the day when Moses sent me. As my strength was then, even so is my strength now, for war, both to go out and to come in.' For fighting, and for all the intercourse and manifold activities of life, his sinews are as braced, his eyes as clear, his spirit and limbs as alert as they were in those old days. No doubt you will say that was due to miraculous intervention. No doubt it was; but is it not true that, in a very real sense, a man may keep himself young all his life, if he will go the right way to work? And the secret of perpetual youthfulness lies here, in giving our hearts to God and in living for Him. Christianity, with its self-restraint and its exhortations to all, and especially to the young, to be chaste and temperate and to subdue the animal passions, has a direct tendency to conserve physical vigour; and Christianity, by the inspiration that it imparts, the stimulus that it gives, and the hopes that it permits us to cherish, has a direct tendency to keep alive in old age all the best of the characteristics of youth. Its buoyancy, its undimmed interest, its cheeriness, its freedom from anxiety and care--all these things are directly ministered to, and preserved by, a life of simple faith that casts itself upon God, and dwells securely, in joy and in restfulness, and not without a great light of hope, even when the shadows of evening are falling. One of the greatest and most blessed of the characteristics of youth is the consciousness that the most of life lies before us; and to a Christian man, in any stage of his earthly life, that consciousness is possible. When he stands on the verge of the last sinking sandbank of time, and the water is up to his ankles, he may well feel that the best and the most of life is yet to be. 'The last of life, for which the first was made: Our times are in His hand Who saith, "A whole I planned. Youth shows but half; trust God: see all, nor be afraid."' 'They shall still bring forth fruit in old age, they shall be full of sap and green.' A gnarled old tree may be green in all its branches, and blossom and fruit may hang together there. The ideal of life is, that into each stage we shall carry the best of the preceding, harmonised with the best of the new, and that is possible to a Christian soul. The fountain of perpetual youth, of which the ancients fabled, is no fable, but a fact; and it rises, where the prophet in his vision saw the stream coming out, from beneath the threshold of the Temple door. IV. So, lastly, I see here a beautiful example of a life which to the last is ready for danger and enterprise.