Most of us are familiar with the ancient Jewish religion, the Law of Moses and the traditions of the Jews spelled out in the Old Testament and in history. There are actually four classifications of world religions which stem from this, all of which are rooted in the promises made to Abraham. There still remains, of course, those Jews that follow, to an extent at least, the original first five books of the Bible...the Jews, or Judaism.
The other three (not our subject for today) are (1)Christianity-founded in AD 32 by our Lord, Jesus Christ, the only begotten son of God. (2)Islam-A false religion started by a false prophet named Muhammad, in the early years of the 7th century AD. (3)Ba'hai: Another false religion started by a false prophet, Bahб'u'llбh, in the latter part of the 19th century AD.
Judaism was the practice of the Jews under the Old Testament law, given them through Moses. After their dispersion, they mingled with all types of people and religions but a number of them still profess to hold on to the law contained in the pentateuch, rejecting the New Testament teachings and that Jesus was the promised Messiah. However, they, along with others who profess to live under that law, fail miserably to adhere to it.
There are varying degrees of strictness as to their adherence to the Mosaical law, from those that do virtually nothing concening it other than circumcision, to those who call themselves "orthodox" who strain at a gnat and swallow a camel. This latter group professes to keep the Sabbath holy, but do not do so according to the strictness of the Law. They attempt to eat only "kosher" foods but most are known to break that rule when hungry and unable to readily get their hands on the "kosher" type.
The subject is much too lengthy to go into detail here, but I am listing a few links on the subject for your information plus a few showing why Jesus is the Messiah that they rejected and therefore are religiously astray.