Isaiah 8:20 - Exposition

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.