8:16 testimony . . . teaching. This could refer to the revelation of God (1:10) to Moses (Deut. 4:44, 45), to Isaiah, or to both.

disciples. Isaiah’s followers wrote down and sealed his prophecy like a law so that it could be known whether it failed or was fulfilled by events (vv. 1, 2, 20). This is the test of a true prophet (Deut. 18:21, 22; Jer. 28:9), through whom God is known and trusted.