To the Law and to the testimony. A sort of watchword or battle-cry, to be used by the faithful when God's enemies assailed them. Compare Gideon's cry ( 7:18), "For the Lord and for Gideon." If they speak not according to this word, it is because there is no light in them; rather, Surely they will speak according to this word, when there is no dawn for them; i.e. when they are plunged in darkness (Isaiah 8:22) and distress, and see no prospect of better days, surely they—the people generally—will rally to this cry, and repeat it, "For the Law and for the testimony." They will not always trust in necromancy.
are supposed by some to be cut of place, and to belong properly to the description of the Assyrian invasion, given in Isaiah 8:7, Isaiah 8:8. But this bold solution of a difficulty is scarcely to be commended, there being no limit to its use. An order followed in all the manuscripts should not be disturbed, if it gives any tolerable sense. Such a sense can, it is thought, be found here by regarding the two verses as exegetical of the last clause of Isaiah 8:20—"when there is no dawn for them."