Which dwellest between the cherubims - The reference is to the shechinah, or miraculous glory, which from time to time appeared above the mercy-seat from between the two cherubims, whose wings overshadowed the ark of the covenant (1 Kings 6:23-27; compare Exodus 25:22; Leviticus 16:2, etc.).
Thou art the God, even thou alone - This is the protest of the pure theist against the intense polytheism of Sennacherib’s letter, which assumes that gods are only gods of particular nations, and that Hezekiah’s God is but one out of an indefinite number, no stronger or more formidable than the rest.