Eli wrote:
It basically quotes R Alshich as saying:   "[Isaiah 52:13] Behold, my servant shall prosper... [Alshech:] I therefore, in my humility, am come after them; [the commentators], not with any sense of the wisdom I am about to utter, but merely with the object of applying to its elucidation a straightforward method, in accordance with the literal sense of the text... I may remark, then, that our Rabbis with one voice accept and affirm the opinion that the prophet is speaking of the King Messiah, and we shall ourselves adhere to the same view."
One last thing (in case it wasn't clear enough in the previous posts) -- notice that this "quote" refers to Isaiah 52:13 -- not to all of Isaiah 53.   R' Alshich, speaking of the servant prospering, related Isaiah 52:13 to King David.     The Targum on Isaiah relates Isaiah 52:13 to the messiah.  Ibn Ezra (1089–1164) is quoted as saying 
"and many explain it as refering to mashiach based on the words of our sages in Midrash Rabah 11:3..."
The missionary wants to give the impression that these learned men said all of this fourth servant song refers to "the" messiah --  to all of Isaiah 53 -- but that is not true.     R' Alshich explicitly states that the servant in Isaiah 53:1-8 is Israel (the Jewish people).

סופי

And everything that Sarah tells you, listen to her voice. Bereshit (Genesis) 21:12