‘In that day will Egypt be like a woman, and it will tremble and fear because of the shaking of the hand of Yahweh of hosts, which he shakes over it. And the land of Judah will become a terror to Egypt, and everyone to whom mention is made of it will be afraid, because of the purpose of Yahweh of hosts which he purposes towards it.'
This is a reversal of the usual position. In the past it was always Judah that feared Egypt, and trembled at the approach of Egyptian armies. But now the tables will be turned. It is Egypt that will quail at the approach of Judah. They will have to face up to Judah's God, recognising His sovereignty. Judah will become predominant.
‘Be like a woman.' That is weak and easily frightened.
It may be that all this is simply expressing the low state to which Egypt have come by exaggeration. It will be so low that they will even become afraid of Judah!
But it may be that the prophet is describing in terms of his own day and understanding the reversal of roles in the future. Instead of Judah being subject to Egypt, Egypt will be subject to Judah. God's people will become so effective that Egypt yields before them. It may thus be intended to be a picture in prophetic terms of the triumphant expansion of the Kingly Rule of God, and the establishing of the throne of David. ‘Out of Zion will go forth the Law, and the word of Yahweh from Jerusalem' (Isaiah 2:3). And Egypt will tremble and submit.
It came about in a different way than anticipated when the soldiers of Christ invaded Egypt with the Gospel of Christ, and with the sword of the Spirit (Ephesians 6:17; Hebrews 4:12) in their hand, and Egypt, at least outwardly, trembled and submitted to His rule. Thus when the multitude which no man can number are assembled before the throne of God (Revelation 7:9), Egypt will be represented there. (As always, by the remnant who in this case will be the true Egypt).