Albert Barnes Commentary Isaiah 30:5

"They shall all be ashamed because of a people that cannot profit them, that are not a help nor profit, but a shame, and also a reproach." — Isaiah 30:5 (ASV)

They were all ashamed – That is, all the legates or ambassadors. When they came into Egypt, they found them either unwilling to enter into an alliance or unable to render them any aid, and they were ashamed that they had sought their assistance rather than depend on God .