Isaiah 48-53 is constantly talking about Jesus in the Trinity. For example,

"From the time anything existed, I was there. And now the Lord God sent Me and His Spirit" (Is. 48.16). Jesus was despised on the cross. "To the one who was despised, to the one abhorred by people, to a servant or rulers" (49.7). The servant brings salvation. "The Lord GOD has given Me the tongue of those who are instructed to know how to sustain the weary with the word" (50.4). "I gave my back to those who beat me" (v.6). "Who among you fears the LORD, listening to the voice of His servant.... This is what you'll get from My hand: you will lie down in a place of torment" (v.10). The hand of Jesus is most authoritative.

Especially read all of chapters 52 & 53.