Isaiah 9:6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. 7 Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even for ever. The zeal of the Lord of hosts will perform this. Not only do muslims believe that that someone corrupted the New Testament at some point but they also believe those same people used a time machine and travelled back in time hundreds of years to rewrite books like Isaiah to insert references like that into the text. That passage is literally talking about someone born into the flesh who will be called “The Mighty God” but Judaism of that time did not have a concept of the son of god yet. It was a prophetic vision of the future birth of the christ child who was both man and god at the same time. It also say that he will be called the Prince of peace and born from the lineage of David. If you try to talk to a Muslim or Jehovah’s Witness about this, they will get really uncomfortable because the old testament predates the birth of christ by centuries.