Charles Ellicott Commentary Isaiah 42:19

"Who is blind, but my servant? or deaf, as my messenger that I send? who is blind as he that is at peace [with me], and blind as Jehovah`s servant?" — Isaiah 42:19 (ASV)

Deaf, as my messenger ... — The work of the messenger of God had been the ideal of Isaiah, as it was of the servant in whom the ideal was realized (Romans 10:15; Isaiah 42:1). But how could a blind and deaf messenger, like the actual Israel, do his work effectively? (Psalms 123:2).

As he who is perfect. — Strictly speaking, the devoted, or surrendered one. The Hebrew meshullam is interesting, as connected with the modern Moslem and Islam, the man resigned to the will of God. The frequent use of this, or a cognate form, as a proper name after the exile (1 Chronicles 9:21; Ezra 8:6; Ezra 10:15; Nehemiah 3:4) may (on either assumption as to the date of 2 Isaiah) be connected with it by some link of causation. Other meanings given to it have been “perfect” as in the Authorized Version, “confident,” “recompensed,” “meritorious.”