I will cause the sword to fall out of his hand - When the arm is broken, the sword will naturally fall. But these expressions show that the Egyptians would be rendered wholly useless to Zedekiah, and should never more recover their political strength. This was the case from the time of the rebellion of Amasis.
Fourth prophecy against Egypt spoken three months before the capture of Jerusalem Ezekiel 26:1, and three months after the prophecy of Ezekiel 29:1. Meantime, Pharaoh-Hophra‘s attempt on Jerusalem had been foiled, and the Egyptians driven back into their own country (Jeremiah 37:5 note).
Ezekiel 30:21
I have broken - Especially by the defeat at Carchemish.
A roller - Or, a bandage.
Ezekiel 30:22
The strong - Such power as Egypt yet retained at home and abroad.
That which was broken - The power which Egypt aimed at ineffectually, the conquest of Palestine and Syria.