What were the international borders and boundaries of Israel in 1948 ?

The "Jewish state" was founded on the basis of an ancient Biblical map, and to this date the "Jewish state" still refuses to declare its borders in favor of future expansion. There is nothing like this Biblical map below to send shivers among Arabs and Muslims, since its borders spans the occupied West Bank (including occupied East Jerusalem), occupied Gaza Strip, southern Lebanon, the western parts of Jordan, and southern Syria including the occupied Golan Heights. This deep fear was also one of the prime motives behind the Palestinian and Arab rejection of the U.N. GA proposed partition plan in 1947 in addition to main reasons which are:
-Indigenous Palestinians being the great majority (Despite the active British assistance to establish a "Jewish National home" in Palestine. As of 1948, Jews made 1/3 of the total population and most importantly only 1/3 of those Jews in Palestine (1/9 of the total population) were citizens of the country and the rest were either illegal immigrants or simply immigrants who were granted entry to Palestine to escape German and European atrocities in Europe.
-Indigenous Palestinian owning more than 93% of the land. The majority of what’s left was bought by Jews from absentee land lords, kicking Palestinian peasants who cultivated and lived in those lands, one of the reasons why Palestinians were against selling lands to Zionists prior to their full ethnic cleansing and dispossession in 1948.
-Palestinian natural love for their homeland where they lived for many centuries.
-They knew the acceptance of it by some Zionists was only a smoke screen for future expansion, colonialism, and land theft of Palestinian land.
For further information check my answer below:
Handala's answer to Is it true that Palestinians sold their lands to Zionists and were not dispossessed in 1948?
Map of Greater Israel as submitted by the Word Zionist Organization soon after the end of WWI:
In that regard, it is worth sharing the following encounter between Pinhas Rozen (Israel's first Justice Minister) and Ben-Gurion (Israel's 1st Prime Minister). Rozen demanded that Israel's Declaration of Independence should cite the country's borders. Ben Gurion objected, and both exchanged the following:

ROZEN: "There's the question of the borders, and it cannot be ignored."

BEN-GURION: "Anything is possible. If we decide here that there's to be no mention of borders, then we won't mention them. Nothing is a priori [imperative]."

ROZEN: "It's not a priori, but it is a legal issue."

BEN-GURION: "The law is whatever people determine it to be." (1949, The First Israelis, p. xviii)

In a letter Chaim Weizmann sent to the Palestine-British high Commissioner while the Peel Commission was convening in 1937, he wrote:

"We Shall spread in the whole country in the course of time ..... this is only an arrangement for the next 25 to 30 years." (Expulsion Of The Palestinians, p. 62)

In 1938, Ben-Gurion made it clear of his support for the establishment of a Jewish state on parts of Palestine ONLY as an intermediary stage, he wrote:

"[I am] satisfied with part of the country, but on the basis of the assumption that after we build up a strong force following the establishment of the state--we will abolish the partition of the country and we will expand to the whole Land of Israel." (Expulsion Of The Palestinians, p. 107, One Palestine Complete,p. 403).

During a lecture in Tel-Aviv in front of Mapai activists in 1938, Ben-Gurion divided the realization of the "historic aim of the Jewish state" into two stages:
The first stage, which would last ten to fifteen years, he called "the period of building and laying foundations." This would prepare the state for the second stage,"the period of expansion." The goal of both stages was the "gathering of the exiles in all of Palestine." And so "from the moment the state is established, it must calculate its actions with an eye toward this distant goal."
One day after the U.N. vote to partition Palestine, Menachem Begin, the commander of the terrorist Jewish organization , Irgun and Israel's future Prime Minster proclaimed:

"The Partition of Palestine is illegal. It will never be recognized .... Jerusalem was and will for ever be our capital. Eretz Israel will be restored to the people of Israel. All of it. And for Ever." (Avi Shlaim, Iron Wall, p. 25).

Ben-Gurion also clearly never believed in static borders, but dynamic ones as described in the Bible. He stated during a discussion with his aides:

"Before the founding of the state, on the eve of its creation, our main interests was self-defense. To a large extent, the creation of the state was an act of self-defense. . . . Many think that we're still at the same stage. But now the issue at hand is conquest, not self-defense. As for setting the borders--- it's an open-ended matter. In the Bible as well as in our history, there all kinds of definitions of the country's borders, so there's no real limit. No border is absolute. If it's a desert--- it could just as well be the other side. If it's sea, it could also be across the sea. The world has always been this way. Only the terms have changed. If they should find a way of reaching other stars, well then, perhaps the whole earth will no longer suffice." (1949,The First Israelis, p.6).

It has been customary among all Zionists leaders to use the Bible to justify perpetrating WAR CRIMES. Regardless of the methods used to build the "Jewish state", the quote above is a classical example how the Bible and the great and ancient religion of Judaism is used to achieve political objectives.
Early Revisionist Zionist groups such as Betar and Irgun Zvai-Leumi regarded Greater Israel as the territory of the Mandate of Palestine including Transjordan. Yitzhak Shamir was a dedicated proponent of Greater Israel and as Israeli Prime Minister gave the settler movement funding and Israeli governmental legitimisation.
Irgun wanted all of Palestine and other lands from Arabic countries like the following picture below:
In his Complete Diaries, Vol. II. p. 711, Theodor Herzl, the founder of Zionism, says that the area of the Jewish State stretches:

"From the Brook of Egypt to the Euphrates."

Rabbi Fischmann, member of the Jewish Agency for Palestine, declared in his testimony to the U.N. Special Committee of Enquiry on 9 July 1947:

"The Promised Land extends from the River of Egypt up to the Euphrates, it includes parts of Syria and Lebanon."

Expansion of Illegal settlements and what you see on the news is Greater Israel in the making, that’s why Israel never officially declared its borders when it declared its so called “Independence”.