He was oppressed, and he was afflicted, yet he opened not his mouth; like a lamb that is led to the slaughter, and like a sheep that before its shearers is silent, so he opened not his mouth.
Barnes' Notes on the Bible:
Yet he opened not his mouth - This means that he was perfectly quiet, meek, submissive, patient, He did not open his mouth to complain of God on account of the great sorrows which he had appointed to him; nor to God on account of his being ill-treated by man. He did not use the language of reviling when he was reviled, nor return upon people the evils which they were inflicting on him (compare Psalm 39:9). How strikingly and literally was this fulfilled in the life of the Lord Jesus! It would seem almost as if it had been written after he lived, and was history rather than prophecy. In no other instance was there ever so striking an example of perfect patience; no other person ever so entirely accorded with the description of the prophet.
He is brought as a lamb to the slaughter - This does not mean that he was led to the slaughter as a lamb is, but that as a lamb which is led to be killed is patient and silent, so was he. He made no resistance. He uttered no complaint. He suffered himself to be led quietly along to be put to death. What a striking and beautiful description! How tender and how true! We can almost see here the meek and patient Redeemer led along without resistance; and amidst the clamor of the multitude that were assembled with various feelings to conduct him to death, himself perfectly silent and composed. With all power at his disposal, yet as quiet and gentle as though he had no power; and with a perfect consciousness that he was going to die, as calm and as gentle as though he were ignorant of the design for which they were leading him forth. This image occurs also in Jeremiah, Jeremiah 11:19, 'But I was like a lamb or an ox that is brought to the slaughter.'
As a sheep - As a sheep submits quietly to the operation of shearing. Compare 1 Peter 2:23, 'Who when he was reviled, reviled not again.' Jesus never opened his mouth to revile or complain. It was opened only to bless those that cursed him, and to pray for his enemies and murderers.