What important idea are the ancient Hebrews credited for starting?

Answer 1

The concept of having a week composed of 7 days, may be a Hebrew invention.

Answer 2

Monotheism, the Ten Commandments, the Torah and the Prophets.
Judaism is egalitarian and values all individuals, both men and women. The wealthy have no privileges; and the poor are valued, treated well and their opinions listened to. (Compare this to those societies in which only mature, land-owning males had any legal status.)
Judaism applied laws, and rules of moral behavior, to all its members equally. The laws of Moses form much of Western legal background.
Quote:
"I will insist that the Hebrews have done more to civilize men than any other nation ... fate had ordained the Jews to be the most essential instrument for civilizing the nations" (John Adams, 2nd President of the United States).
"Certainly, the world without the Jews would have been a radically different place. Humanity might have eventually stumbled upon all the Jewish insights, but we cannot be sure. All the great conceptual discoveries of the human intellect seem obvious and inescapable once they had been revealed, but it requires a special genius to formulate them for the first time. The Jews had this gift. To them we owe the idea of equality before the law, both Divine and human; of the sanctity of life and the dignity of human person; of the individual conscience and of collective conscience, and social responsibility" (Paul Johnson, Christian historian, author of A History of the Jews and A History of Christianity).

Answer 2

The long, rich history of Judaism gives the Western world much of its shape today. Many of the laws, traditions, culture and values are directly attributable to Judaism.Link: History of Judaism

• The Jews' monotheistic religious tradition (Deuteronomy 6:4) shaped the Western beliefs about God.

Link: Monotheistic religious tradition

• The 7-day week (Exodus ch.20), including a day of rest for everyone. This weekly rest was a concept unique to the Israelites.

• The concept of morality (Leviticus ch.18-19) was also the work of the Hebrews, including the dignity (Genesis 5:1) and value of a person (unlike idolatry, which had no moral character whatsoever; with worship of the gods accompanied by practices such as human sacrifice, "sacred" prostitution, and animal worship).

Link: Morality

• Women's rights were carefully maintained in Judaism. Israelite women could own property, could initiate court cases, could have their own servants, and could own fields and businesses; and the Torah specifies marital rights for women (Exodus 21:10).

• Under Israelite law, everyone had recourse to the courts. A child, widow, wife, poor person, etc., could initiate legal action against any citizen to redress perpetrated harm. Compare this to those societies in which only mature, land-owning males had any legal status.

• The Western diet reflects some of the Judaic dietary law. With the exception of the pig, Western society does not eat species not contained in kosher law (Deuteronomy ch.14). Owls, mice, insects, rats, snakes, cats and dogs are not eaten by most Westerners and it is a direct result of Jewish culture.

• Parents are responsible for teaching children (Deuteronomy ch.11). Illiteracy among Israelites, in every generation, was rare. Universal education in the Western world is taken for granted today, yet this is a recent development. In Judaism, however, it goes back for more than 3300 years. Judaism has always maintained that education is the highest goal of man in his pursuit of godliness. This tradition has now been passed on to Western culture.

• Infants are to be cherished, protected and cared for, whether or not they turned out to be the gender you were hoping for. Compare this to societies in which unhealthy babies, or females, were killed.

• Cruelty to animals is not acceptable.

• Government is accountable to a higher authority. In other ancient societies, the monarch was all-powerful. Among the Israelites, however, the king was under the constant scrutiny of the Divinely-informed prophets, who didn't hesitate to castigate him publicly for any misstep in the sight of God. And, other than for the crime of rebellion, the king couldn't punish any citizen by his own decision. He was obligated by the Torah-procedures like everyone else (Talmud, Sanhedrin 19a).

Link: Israelite prophets

• A robber repays double to his victim (Exodus 22:3), or works it off. Cutting off the hands of a robber is a punishable crime. Debtors are not imprisoned or harmed. They are made to sell property and/or work to repay what they owe. Compare this to the Roman practice by which anyone could accuse a man of owing them money and the debtor could be killed (Roman "Twelve Tables of Law" code, 3:10).

• Western jurisprudence in general is based in part upon Judaic Torah-observance. A quick look at the Ten Commandments (Exodus 20) and the laws that follow (Exodus ch.21-23) gives a summary of most modern law.

• It is the responsibility of the community to support the poor (Deuteronomy ch.15), the widow, the orphan, and the stranger passing through (Exodus 22:20-21).

• It is important to note that all of the above were instituted among the Hebrews (a.k.a. the Israelites) thousands of years earlier than in other nations. Here's one example: Infanticide was practiced among classical European nations until it was stopped by the influence of Judaism and its daughter-religions. Professor and former President of the American Historical Association, William L. Langer (in The History of Childhood): "Children, being physically unable to resist aggression, were the victims of forces over which they had no control, and they were abused in almost unimaginable ways."
  

Link: Infanticide was practiced

• See also other the other Related Links.
  

Link: More about Judaism's impact

Link: How did Jewish ideas spread?