Isaiah 8:20

The law.. the testimony] i.e. Isaiah's own teaching, which, by his direction, had been written down and carefully preserved (Isaiah 8:16).

If they speak not, etc.] The meaning seems to be, 'If they speak not according to this word' (viz. 'to the law and to the testimony') 'surely there is no morning for them' (RV): i.e. the only hope of a brighter dawn lies in being guided by Isaiah's teaching. But another rendering is possible, 'Surely according to this word shall they speak for whom there is no morning' (RM), i.e. they will recognise too late the value of the principles inculcated by Isaiah.