What are the biblical borders of Israel?

Generally speaking, the Prat and the Nile are the main reference points, as are the Mediterranean Sea and the Red Sea. According to the Rambam Eretz Yisrael is between latitude 29 and latitude 35.

There are seven places in the Torah that mention the boundaries of Eretz Yisrael, some partial and some complete.  The first time - at the mention of the Prat River (Bereshit/Genesis 2:10-14), then Bereshit/Genesis 15:18, Shmot/Exodus 23, Parashat Mas'ei (Bamidbar), Devarim/Deut. 1:6-7, the
end of Parashat Ekev, Devarim/Deut. 34:1-4.

I have heard that there are some Jews who think that there shouldn't be a state of Israel until the Messiah comes.  Is this true?

Yes, there are some who interpret scripture to mean that until King Messiah is ruling on the Throne of David,

Israel is not truly Israel, the nation of the Most High.  It is a relative minority that holds this view and they pray fervently for the coming of the Messianic Age.  We appreciate their prayers to this end.  May their prayers be answered even in our time!

Dear Leah,  I was watching A&E network the other night.  They did a story about the history of the Jews becoming a nation and the different battles they had to fight to keep Israel.  They said they used military force to drive out the Brits sometime in the fourties.  My question is did they have to use force against Britain to force them to leave Israel?

British forces conquered what was then Palestine from the Turks towards the end of World War I, and remained there under a Mandate legislated in 1920 by the League of Nations . Under the terms of that Mandate, which recognized 'the historical connection of the Jewish people with Palestine' and 'the grounds for reconstituting their national home in that country', Britain was to help prepare the Jewish people for political independence in Palestine . One of Britain's first acts as Mandatory Power in Palestine was to sever the eastern portion of Palestine, Transjordan, comprising more than three-quarters of the total area, and to earmark it for Arab sovereignty. (This later became the Hashemite Kingdom of Jordan.)  The remaining part of the country, from the Jordan River to the Mediterranean Sea , was to be developed by the Jews and eventually turned into a Jewish state.

While a number of local Arab leaders were ready for such an arrangement, a militant group led by the Mufti of Jerusalem, Haj Amin el- Husseini , declared an all-out war against Jewish independence in ANY part of Palestine Attacks and acts of terror, not only against Jews and Jewish villages but also against the Arab moderates who wanted peace with the Jews, became the order of the day. The British, in trying to deal with these outbreaks of violence, heavily favored the Arab side; for example, by severely restricting Jewish immigration into the country (even after the Nazi persecution of Jews in Germany began, and even after the Holocaust in the 1940s), while at the same time allowing both legal and illegal Arab immigration to proceed unchecked. The British also played an active role in arming and training the Arab militias, in both parts of Palestine- Transjordan, at the expense of the Jewish forces, whose efforts to obtain arms for their defense were thwarted at every turn.

Despite these and other provocations by the British, the official Jewish defense organization, the Haganah , adopted a policy of restraint vis-à-vis the occupying force. When, however, Britain's anti-Jewish policies and actions continued even after the outbreak of World War II in the early 1940s, two Jewish underground movements sprang up that went into action against the British forces in Palestine . It is believed that the pressure they exerted on these forces, coupled with Britain's growing frustration at its inability to bring the Arab-Jewish conflict to an end, contributed to Britain's decision, in 1946, to withdraw from Palestine and hand the problem over to the newly formed United Nations. The UN General Assembly subsequently (on Nov. 29, 1947) recommended the partition of Palestine into Jewish and Arab states, a recommendation that was accepted by the Jews, in the spirit of a compromise for peace, but totally rejected by the militant Palestinian Arabs and by all the Arab states in the region, who then went to war against the Jewish population of the country.

The British forces left Palestine on May 14, 1948. That same day Israel, acting on the UN resolution of Nov. 29, proclaimed its independence; and on the following day, May 15, the armies of five Arab states, and contingents from two others, invaded Palestine with the avowed intention of wiping Israel out at the very moment of its modern rebirth. It only remains to say that, with G- d's help, that intention was frustrated, and in the war that ensued, “ Israel's War of Liberation“, the invading armies, which greatly outnumbered the Jewish defenders, were nevertheless roundly defeated, and Israel Reborn became a fact of history.

Thanks to Moshe Aumann, retired diplomat with Israel's Foreign Ministry, for providing this thorough answer!