I. There are many terms applied to God in Scripture, which seem to anthropomorphize His character: The "angry" God; the "repenting" God; the "foreseeing" God. Now, whenever such terms are used, think of them as steps of Divine descent. Through those words, as down a stairway, Divine Majesty descends to us, and infinite relations make themselves known. "Jealous" is the same word as zealous, and both are derived from the Greek word ζῆλος, fire. Zeal is enthusiasm, moral fire; and jealousy what is jealousy, but love on fire? And is not this the representation we constantly have of God? And is it possible that to us He could be what He is love if it were not so? Jealousy is love on fire, and the jealousy of God is love on fire.
II. From our most innocent down to our most corrupt affections, there is danger that in them, in our haste, we forget God. If you love unwisely and vehemently, whatever it may be, you must accept the consequences as a proof of Divine jealousy. God is jealous of sin; and being jealous of sin, He is jealous of all aberrations from Himself. He is jealous of love, of power, of knowledge. See how He is constantly reminding man of his weakness, as He incarnates his strength. And God is constantly absorbing man's knowledge, love, and power to Himself.
III. We feel that there is no love where there is no fire; but let it burn with the white, not with the red, heat. Christ was love on fire. God so loved the world that He gave Him. The Cross illustrates the jealousy of God.
E. Paxton Hood, Dark Sayings on a Harp,p. 111.
Reference: Nahum 1:2. Spurgeon, Morning by Morning,p. 256.