Apocalypse Explained # 516
516. And the third angel sounded.- This signifies influx out of heaven, and thence the third change with the evil, as is evident from what was said and shown above (n. 502).
Exodus 23:31
31
I will set your border from the Red Sea even to the sea of the Philistines, and from the wilderness to the River; for I will deliver the inhabitants of the land into your hand, and you shall drive them out before you.