John 12:41

In the vision that Isaiah recorded in Isaiah 6, the prophet wrote that he saw God’s glory (Isaiah 6:3). Now John wrote that Isaiah saw Jesus’ glory and spoke of Jesus. Obviously John regarded Jesus as God (cf. John 1:18; John 10:30; John 20:28; Colossians 2:9). Isaiah had spoken of Jesus in that he had revealed many messianic prophecies. Earlier Jesus had claimed that Moses had written about Him (John 5:46).

These quotations justify interpreting the Old Testament servant of the Lord passages as referring to the Messiah. There has long been a debate within Judaism and liberal Christianity about whether these passages refer to a personal Messiah or only to Israel.