The Bible does not say anything about Christians supporting or standing up for Jews in those exact words. Those who do are doing so based on the promise given to Abraham when God called him from out of Ur of the Chaldeans. In Genesis 12:3 God said, "I will bless the ones blessing you, and I will curse the ones cursing you; and in you all the families of the earth shall be blessed" (Literal Translation). Many take this to mean that if you are for Israel and support them, you will be blessed and those who oppose them will be cursed.