Isaiah 8:16

Bind up] i.e. tie up the parchment roll on which the prophet's teaching has been written, and lay it aside to be consulted later.

The testimony] i.e. the inspired admonition which the prophet has just delivered. The law] not referring to the written law of God, but used in the wide sense of 'instruction' or 'teaching' (RM): the inspired teaching given by the prophet himself (cp. Isaiah 1:10; Isaiah 5:24; Isaiah 30:9), which he commits to writing and delivers to his disciples.