In his very informative 1928 book “Adjustment of Law to Life in Rabbinic Literature,” Solomon Zucrow, shows, as did many others, that current Jewish law is radically different than what is stated in the Hebrew Bible. Many Orthodox Jews say that the differences were ordered by God, that when God revealed the Torah to Moses, God gave an “Oral Torah” together with the “Written Torah.” It was as if God admonished Moses, when I ordered you to write “‘an eye for an eye,’ I want you to tell the people this does not mean what it says, it means people must pay money when they damage another person. And when I insisted three times that one must not boil a kid in its mother’s milk, they must not take the words literally, but understand that I mean to say, observe laws of kashrut and not eat dairy products after meat product until waiting six hours.”
I addressed this situation in my books. In “Mystery of Judaism,” I explained why every single holiday mentioned in the Torah, without exception, was changed from what the Torah requires and I explained why this happened. In my “Mysteries of Judaism II,” I gave numerous examples of how the rabbis and others changed biblical laws and explained why this was done, including the view of Maimonides that the Torah itself wanted changes to be made.
Zucrow’s book is only 186 pages long, but it contains much information about “the various methods and their underlying principles whereby the rabbis harmonized life and religion so that Judaism might be adapted to life and its changes in all times.” He lists some of the biblical laws which were abrogated. For example (1) the law of eglah arufah, breaking a heifer’s neck in Deuteronomy 21:3, 4 when a murdered man is discovered near a city; (2) the ordeal of jealousy by a man concerning his wife in Numbers 5:12; (3) the destruction of a city tainted with idolatry in Deuteronomy 12:13, 14; (4) an eye for an eye in Exodus 21:24, Leviticus 24:19, 20; (5) the execution of a man whose ox caused the death of a man in Exodus 21:28, 29; (6) starting the year with the seventh month in violation of Exodus 12:1 where the month in which the exodus occurred is clearly called the first month; (7) giving the tithes which Numbers 18:21, 22 states should go to the Levites to the priests; (8) changing the age in which Levites enter the service in the sanctuary from 30 in Numbers 4:3 and 25 in Numbers 8:24 to 20; (9) allowing one to live in Egypt despite the prohibition of Deuteronomy 17:16; (10) the killing of a stubborn son in Deuteronomy 21:18; (11) sacrifices which make up a considerable portion of the Torah were discontinued, as well as (12) the laws of slavery, and many dozens more.
Zucrow lists many reasons why laws were either changed or annulled entirely. In essence, the reasons boil down to one: times changed and the community needed the laws to be altered to fit their new conditions. The rabbis justified the revisions by saying things such as “it is proper to break a biblical law if religion in general might thereby be strengthened” and they spoke of “the needs of society.”
Sometimes they disguised the changes by developing a legal fiction which effectively annuls the biblical mandate, as Hillel did with his pruzbal which allowed loans to remain in effect despite Deuteronomy 15:9 requiring them to cease in the sabbatical year which occurred every seventh year; the selling of chametz, leaven products, before Passover, although the Torah demands the total removal of leaven products from the home; the erev which allows people to carry on the Shabbat; fictitious sale of property to a non-Jew before the Shabbat so that a merchant can sell items on the Shabbat; a procedure allowing lending money with interest; and other legal fictions.
 Exodus 23:19, 34:26, Deuteronomy 14:21. In his Guide of the Perplexed 3:48, Maimonides wrote that eating such a mixture makes one overfull, “but I think that most probably it is also prohibited because it is somehow connected with idolatry,” part of some festival of the heathens. The custom of waiting hours varies; some wait only an hour to eat dairy after eating meat.
 Discussed in Yebamoth 86b.
 Maimonides decided to settle in Egypt rather than in Israel because he found the Jews in Israel at that time to be unwise.
 In the process of time Hillel’s pruzbal and the heteir Isko for loans at interest have been discarded and people engage in the loans as if they were never prohibited by the Torah.