Keil & Delitzsch, on Eccl 3:14

"Thus I discerned it then, that all that God will do exists for ever; nothing is to be added to it, and nothing taken from it: God has thus directed it, that men should fear before Him." This is a conclusion derived from the facts of experience, a truth that is valid for the present and for the time to come. We may with equal correctness render by quidquid facit and quidquid faciet. But the pred. shows that the fut. expression is also thought of as fut.; for הוּ יה לע does not mean: that is for ever (Hitz.), which would be expressed by the subst. clause הוּא לעולם; but: that shall be for ever (Zck.), i.e., will always assert its validity. That which is affirmed here is true of God's directing and guiding events in the natural world, as well as of the announcements of His will and His controlling and directing providence in the history of human affairs. All this is removed beyond the power of the creature to alter it. The meaning is not that one ought not to add to or to take from it (Deu 13:1; Pro 30:6), but that such a thing cannot be done (vid., Sir. 18:5). And this unchangeableness characterizing the arrangements of God has this as its aim, that men should fear Him who is the All-conditioning and is Himself unconditioned: he has done it that they (men) should fear before Him, אשׂה שׁ, fecit ut; cf. Eze 36:27. ποιεῖν ἳνα, Rev 13:15; and "fear before Him," as at Ecc 8:12.; cf. Ch1 16:30 with Psa 96:9. The unchangeableness of God's action shows itself in this, that in the course of history similar phenomena repeat themselves; for the fundamental principles, the causal connections, the norms of God's government, remain always the same.