Though he was harshly treated,
he submitted and opened not
his mouth

OLD TESTAMENT
Isaiah 53:7
He was oppressed, and he was afflicted, yet he opened not his mouth: he is brought as a lamb to the slaughter, and as a sheep before her shearers is dumb, so he openeth not his mouth. (KJV)

NEW TESTAMENT
Matthew 27:12-14
And when he was accused of the chief priests and elders, he answered nothing. Then said Pilate unto him, Hearest thou not how many things they witness against thee? And he answered him to never a word; insomuch that the governor marvelled greatly. (KJV)
Acts 8:27-35
And he arose and went: and, behold, a man of Ethiopia, an eunuch of great authority under Candace queen of the Ethiopians, who had the charge of all her treasure, and had come to Jerusalem for to worship, Was returning, and sitting in his chariot read Esaias the prophet. Then the Spirit said unto Philip, Go near, and join thyself to this chariot. And Philip ran thither to him, and heard him read the prophet Esaias, and said, Understandest thou what thou readest? And he said, How can I, except some man should guide me? And he desired Philip that he would come up and sit with him. The place of the scripture which he read was this, He was led as a sheep to the slaughter; and like a lamb dumb before his shearer, so opened he not his mouth: In his humiliation his judgment was taken away: and who shall declare his generation? for his life is taken from the earth. And the eunuch answered Philip, and said, I pray thee, of whom speaketh the prophet this? of himself, or of some other man? Then Philip opened his mouth, and began at the same scripture, and preached unto him Jesus. (KJV)