Jesus says no branch can bear fruit by itself. A branch can only bear fruit if it remains in the vine. (So if it’s a detached tree branch that was never even part of a vine to begin with, it definitely can’t bear fruit, then.)

But the Old Testament says Aaron’s staff once sprouted, budded, blossomed, and produced almonds, which are fruit seeds. So either Jesus proves the Old Testament is wrong, or the Old Testament proves Jesus is wrong.

Possible explanations

Maybe Aaron’s staff was made from a trunk rather than a branch, but God decided to make it act like a branch anyway. Or maybe God decided to make the branch grow fruit seeds without the fruit, for some reason.