as the grass = as grass. The reference in verses: Psa_129:6, Psa_129:7 is not to "Egyptian monuments", but to the reply of Jehovah concerning Sennacherib, which Hezekiah quotes here. Compare 2Ki_19:25, 2Ki_19:26. Isa_37:27.
groweth up. Either unsheatheth itself into flower, or is plucked up (as Septuagint and Vulgate)