21 Now, behold, you trust in the staff of this bruised reed, even in Egypt. If a man leans on it, it will go into his hand, and pierce it. So is Pharaoh king of Egypt to all who trust on him.
*Minor differences ignored. Grouped by changes, with first version listed as example.
This bruised reed - The "tall reed of the Nile bulrush" fitly symbolized the land where it grew. Apparently strong and firm, it was quite unworthy of trust. Let a man lean upon it, and the rotten support instantly gave way, wounding the hand that stayed itself so insecurely. So it was with Egypt throughout the whole period of Jewish history (compare 2-Kings 17:4-6). Her actual practice was to pretend friendship, to hold out hopes of support, and then to fail in time of need.
The staff of this bruised reed - Egypt had already been greatly bruised and broken, through the wars carried on against it by the Assyrians.
Now, behold, thou trustest upon the staff of this bruised reed, [even] upon (g) Egypt, on which if a man lean, it will go into his hand, and pierce it: so [is] Pharaoh king of Egypt unto all that trust on him.
(g) Egypt will not only be unable to help you, but will be a detriment to you.
On Egypt? "that broken reed, which runs into the hand of any one who would lean upon it (thinking it whole), and pierces it through." This figure, which is repeated in Ezekiel 29:6-7, is so far suitably chosen, that the Nile, representing Egypt, is rich in reeds. What Rabshakeh says of Egypt here, Isaiah had already earnestly impressed upon his people (Isaiah 30:3-5), to warn them against trusting in the support of Egypt, from which one party in the nation expected help against Assyria.
This broken reed - Whoever trusts in man, leans on a broken reed: but God is the rock of ages.
*More commentary available at chapter level.