Commentary for Isaiah 46:4

And until old age that you have aged and your strength is depleted, that you have no merit, I am the same with My mercy and with My trait of goodness to save you and to bear you and to carry you and deliver you. Since he says regarding their deity, that it is carried and also that it cannot deliver its burden, he says, “But I bear others, and I will deliver My burden.”

And even to old age, etc. This is a figurative expression; it means since the day they had become the people of the Lord for ever.

I have made the Israelites; I am, therefore, not like the gods of Babylon; the Babylonians make their gods. And I will carry and deliver the Israelites; while the idols cannot deliver the burden.