Many people think of Judaism as the religion of cold, harsh laws, to be contrasted with Christianity, the religion of love and brotherhood. This is an unfair characterization of both Judaism and Jewish law. Love and kindness have been a part of Judaism from the very beginning. When Jesus said, "love thy neighbor as thyself," he was merely quoting Torah, from the book that is most commonly dismissed as a source of harsh laws: Leviticus 19:18. The point is expanded in Leviticus 19:34: love [the stranger] as thyself.
A large part of Jewish law is about treating people with kindness. The same body of Jewish law that commands us to eat only kosher food and not to turn on lights on Shabbat, also commands us to love both Jews and strangers, to give tzedakah (charity) to the poor and needy, and not to wrong anyone in speech or in business. In fact, acts of kindness are so much a part of Jewish law that the word mitzvah (מִצְוָה literally, "commandment") is informally used to mean any good deed.
Pirkei Avot, a book of the Mishnah, teaches that the universe depends on three things: on Torah (law), on avodah (service to G-d), and on g'milut chasadim (usually translated as "acts of lovingkindness") (Avot 1:2), perhaps drawing from Psalm 89:3, "the universe is built on kindness" (עוֹלָם חֶסֶד יִבָּנֶה, though this is commonly translated in other ways). In fact, this quote has become a popular song in synagogues: Al Shlosha D'varim (עַל שְׁלשָׁה דְבָרִים, On Three Things). The Mishnah also describes g'milut chasadim as one of the few mitzvot (commandments) for which there is no minimum amount sufficient to satisfy your obligation. (Pe'ah 1:1; reiterated in Talmud Chagigah 7a). That verse also describes g'milut chasadim as one of the few things that one derive benefit from in this world and yet still be rewarded for in the world to come. The Talmud says that g'milut chasadim is greater than tzedakah (charity), because unlike tzedakah, g'milut chasadim can be done for both poor and rich, both the living and the dead, and can be done with money or with acts. (Talmud Sukkah 49b).
The Talmud tells a story of Rabbi Hillel, who lived around the time of Jesus. A pagan came to him saying that he would convert to Judaism if Hillel could teach him the whole of the Torah in the time he could stand on one foot. Rabbi Hillel replied, "What is hateful to yourself, do not do to your fellow man. That is the whole Torah; the rest is just commentary. Go and study it." (Talmud Shabbat 31a). Sounds a lot like Jesus' "Golden Rule"? But this idea was a fundamental part of Judaism long before Hillel or Jesus. It is a common-sense application of the Torah commandment to love your neighbor as yourself (Lev. 19:18), which Rabbi Akiba described as the essence of the Torah (according to Rashi's commentary on the verse).
The true difference between Judaism and Christianity lies in Hillel's last comment: Go and study it. Judaism is not content to leave love and brotherhood as a lofty ideal, to be fulfilled as each individual sees fit. Judaism spells out, in intricate detail, how we are meant to show that love.
Jewish law includes within it a blueprint for a just and ethical society, where no one takes from another or harms another or takes advantage of another, but everyone gives to one another and helps one another and protects one another. Again, these are not merely high ideals; the means for fulfilling these ideals are spelled out in the 613 commandments.
Everyone knows that the Ten Commandments command us not to murder. The full scope of Jewish law goes much farther in requiring us to protect our fellow man. We are commanded not to leave a condition that may cause harm, to construct our homes in ways that will prevent people from being harmed, and to help a person whose life is in danger, so long as it does not put our own lives in danger. These commandments regarding the preservation of life are so important in Judaism that they override all of the ritual observances that people think are the most important part of Judaism. Almost any commandment may be violated to save a life.
We are commanded to help those in need, both in physical need and financial need. The Torah commands us to help a neighbor with his burden, and help load or unload his beast. See Treatment of Animals. We are required to give money to the poor and needy, and not to turn them away empty handed. See Tzedakah: Charity.
Jewish law forbids us from cheating another or taking advantage of another. Jewish law regarding business ethics and practices is extensive. It regulates conduct between a businessman and his customer (for example, not to use false weights and measures, not to do wrong in buying and selling, not to charge interest) and between a business man and his employee (to pay wages promptly, to allow a worker in the field to eat the produce he is harvesting, and not to take produce other than what you can eat from the employer while harvesting).
Entire books have been written on the subject of Jewish laws against wronging another person in speech. We are commanded not to tell lies about a person, nor even uncomplimentary things that are true. We are commanded to speak the truth, to fulfill our promises, and not to deceive others. See Speech and Lashon Ha-Ra.
Contrary to what many people think, most of these laws regarding treatment of others apply not only to our treatment of our fellow Jews, but also to our treatment of gentiles, and in many cases even to our treatment of animals. In fact, some of the laws instituted by the sages even extend kind treatment to inanimate objects. The bread on the Shabbat table is covered during the blessing over the wine, so that it's "feelings" are not hurt by having the wine take precedence over it. Of course, we do not believe that bread actually has feelings, but this practice helps to instill an enormous sensitivity to others. If we can show concern for a loaf of bread, how can we fail to show concern for our fellow man?