Psalms 92:14

They shall still bring forth fruit in old age - As a tree that is carefully planted and cultivated may be expected to live long, and to bear fruit even when it is old. It is true that such a tree may be cut down; or that it may be blown down by winds and tempests; or that it may be unproductive, but as a general rule, and as laying the foundation of a reasonable hope, such a tree may be expected to live long, and to produce fruit even when it is old. So of one devoted early to God, and trained up under the influences of religion. The care, the culture, the habits of temperance, of industry, of moderation, and of sobriety so formed, are favorable to length of days, and lay the foundation for usefulness when old age comes. An aged man should be useful. He should feel that whatever wisdom he may possess as the result of long study and experience, belongs to God and to truth; that one great reason for sparing him is that he may be useful; that the world needs the benefit of his counsel and his prayers; that his life is lengthened out not for his own ease or enjoyment, but that virtue and piety may be extended in the world by all the influence which he can bring to bear upon it in advanced years. It may be added that, as a matter of fact, those who are thus trained and are thus preserved, are useful in old age. No one thus spared need be useless; perhaps almost none are. There is something appropriate for old men to do, as there is for the young and the middle-aged; and it should be the object of an aged Christian to find out what that is, and to do it. The word rendered “old age means literally grey or hoary hair.”

They shall be fat - The meaning is, that they shall be vigorous, or have the appearance of vigor and health.

And flourishing - Margin, as in Hebrew, “green.” This image is taken from a tree, as if it were still green in old age, or gave no indications of decay.