messianic judaism is a movement of jews who believe that jesus (called by them with his hebrew name "yeshua") is the jewish messiah, and who perform this belief in a jewish way (observing the regulations of the torah etc.). they are called "messianic jews". the main branches of judaism do not consider messianic judaism to be judaism, but rather a form of christianity, because judaism rejects jesus/yeshua as the jewish messiah.