Scripture certainly emphasises in many places the frail and fleeting aspect of life; the thought of man's mortality runs as a wail through many a psalm, and touches with pathos the heart of the prophet in his brightest visions. But then there is always in Scripture another side of the picture; and this is the higher, and in the sense of Scripture the truer, side. The good is the original, the substantive of which evil is the inversion. The good is being; the evil is but negation of being.
I. This Psalm, so venerable in its materials that it has been attributed to Moses, is in the main a psalm of mortality; and yet its primary thought is not mortality, but eternity. It opens with the note of eternal being. The idea of the eternal stands as a great light in front of the darkness. Man is mortal, but God is; and God is the Eternal, the home, the dwelling-place, of all generations. This is the grand peculiarity of Hebrew and of Christian thought, that God is first, man only second; that the eternal Being is the true Being, the present visible or transitory being only the derivative being, appearing and then vanishing away, according to the direction of the other.
II. But there is more in this brief word than the general assertion of eternal being, and of a great primary power directing, controlling, all nature and all life. The character of this Being is further so far defined. It is represented not only that God is, but that He is personal. The idea of God is everywhere noted by the personal pronouns "I;" "Thou;" "I am that I am;" "I am the Lord, and there is none else." The word "personality" simply means that God is moral; that He is a character as well as an energy; that He is a Being full of affection, and care, and thoughtful and deliberate love. He is not only Creator: He is Father. The assurance is that we have a supreme Heart above us, responsive to our hearts; that there is a spiritual home encompassing us, a life that changes not with the varying pulses of our thought and feeling.
J. Tulloch, Contemporary Pulpit,vol. i., p. 297.
References: Psalms 90:1; Psalms 90:2. A. M. Fairbairn, The City of God,p. 35.Psalms 90:1-12. Spurgeon, Sermons,vol. xi., No. 59. Psalms 90:2. A. Mursell, Old Testament Outlines,p. 131.