What do you think of Matthew 15:24, Matthew 10:5 and Matthew 19:28 then?
Were they also for us?
In 15:24, Jesus is saying what prophecy said. He was sent to the Jews first. His coming was the fulfillment of Gods Covenant to the Jews. (see Romans 9:5-8) (Romans 1:16)
Matthew 10:5 is the same as above. Salvation was to the Jew first. Key word being first.
I believe that Matthew 19:28 refers to those Jews by birth who denied Jesus being judged. This does not justify saying that his teachings were for the Jews only. Fulfilling Prophecy was required to establish that Jesus was the promised Messiah.
Even in the instance where Jews are spoken of directly does not mean that those Scriptures are not for us. We can learn from all Scripture. Much of the Old Testament was for the Jews, but it all serves to educate us today. Every teaching of Jesus has value for the Christians of today I believe.