Albert Barnes' Notes on the Whole Bible - Isaiah 42:4
He shall not fail - He shall not be weak, feeble, or disheartened. However much there may be that shall tend to discourage, yet his purpose is fixed, and he will pursue it with steadiness and ardor until the great work shall be fully accomplished. There may be an allusion in the Hebrew word here (יכהה yı̂kheh) to that which is applied to the flax (כהה kēhâh); and the idea may be that he shall not become in his purposes like the smoking, flickering, dying flame of a lamp. There shall never be... read more
The Pulpit Commentary - Isaiah 42:4
Divine persistency. "He shall not fail nor be discouraged." "He shall not burn dimly nor be crushed." The figure prominent in the mind of the prophet is not the actual Israel, the ideal Israel, Cyrus, or Judas Maccabaeus, but the Messiah who , in the deepest view of him, is the manifested God. And "though be meets with hard service and much opposition, and foresees how ungrateful the world will be, yet he goes on with his part of the work, till he is able to say, 'It is finished!' and he... read more