It is said that when Prime Minister Menachem Begin is called upon to defend Israel's settlement policy in the West Bank, he instictively reaches for a Bible and a thumbworn Army map kept at hand for the purpose.

After nearly three years in office, however, Begin does not need props. He recites his familiar litany flawlessly, whether for a visiting U.S. congressman, Hadassah women at a Holy Land convention, or journalists who have heard it so often they sometimes silently mouth the words in unison while they doodle on notepads.

But the intermingling of mysticism and military pragmatism has always been a part of Begin's defense of the 60 Jewish civilian outposts scattered across the rocky hillsides and fertile valleys of the 2,300-square-mile West Bank. Sometimes more emphasis is on the mystical claims to the Biblical lands of Israel, and sometimes the weight of the argument is insecurity. But the two elements are always there, as the mood and political inclination of the listener dictate.

Now, with a new groundswell of international opinion against Israel's settlement policies -- inspired by the U.N. Security Council's unanimous condemnation of the outposts -- supporters of Begin's rightist Likud government are scurrying more to their military textbooks than to their Bibles in search of a convincing case.

Apparently convinced that the theme of Israel's biblical right to the West Bank will not fly in Peoria or Paris, Israel's image-makers have begun returning with increasing intensity to the argument that the settlements provide security, which throughout the previous Labor Party government's administration of the occupied territories was an accepted strategic concept.

Under the Labor government, the policy was clean-cut: Israel would build paramilitary settlements in strategically important areas of the West Bank and gradually convert them into civilian outposts that would serve as early-warning stations in case of Arab attack and as productive agricultural and industrial bases.

Between 1967 and 1977, the Labor governmet built scores of settlements in two narrow belts, one stretching the length of the West Bank along the Jordan Valley and the other along the highland ridges overlooking the Jordan River.

When the moment came for making peace, the government and then-foreign minister Yigael Allon theorized, the more densely populated Arab areas west of the settlement lines could be exchanged for a treaty and the strategically essential settlements would remain in Israel's hands.

In contrast, Begin campaigned under the Likud banner on a promise to annex the West Bank. Or, failing that because of international constraints, he promised that the government at least would establish such an extensive de facto presence in the West Bank that returning to the pre-1967 border would be unthinkable.

Encouraged by the ultranationalist settlement movement, the Gush Emunim (faith bloc), and the National Religious Party, a pivotal partner in the parliamentary coalition, the Likud embarked on an aggresive settlement program that stretched all the way from Jenin, in the north, to Hebron, the West Bank's southermost city.

As it now attempts to justify those projects -- and others still on the drawing board -- on the basis of security needs, Begin's government faces some troubling critics.

To the claim that the settlements are urgently needed as a front-line defense against Arab aggression, the critics are reminding the government that minutes before the outbreak of the Yom Kippur war in 1973, the Israel Army headquarters ordered the evacuation of border settlements in the occupied Syrian Golan Heights.

A similiar argument was posed in October during a supreme court hearing on the legality of the Elon Moreh settlement near Nablus, when two prominent retired Army generals, Mattiyahy Peled and former chief of staff Haim Bar-Lev, testified that the settlement might actually hinder military operations in case of war. The Army would have to rush units to the settlements to prevent a massacre of civilians, thereby compromising manpower needs elsewhere, the generals said.

During the same court case, Defense Minister Ezer Weizman refused to support the government's claim that the settlements are essential to Israel's security. Since then, Weizman has kept his distance from subsequent settlement controversies, arguing on occasion that Israel's strained budget might better provide for tanks and aircraft instead of prefabricated houses for Bible-inspired settlers.

Hirsch Goodman, the respected military affairs correspondent for the Jerusalem Post, wrote recently, "the feasibility of settlements as a function of defense seems doubtful.On analysis, one suspects that they actually hamper the smoothe conduct of war and the country's ability to deal cohesively with a frontal attack."

Moreover, other observers have pointed out that putting settlements close to enemy borders seems to undermine the old Israeli argument that giving up the West Bank would put Jewish population centers such as Tel Aviv and Netanya just nine miles from the Arab frontier.By building settlements the critcis say, Israelis putting Jewish population even closer to Syrian and Jordanian artillery.

Another prosettlement argument is that outposts are needed to reduce terrorist activity. Critics say the outposts create targets for terrorists and incite Arab hatred because of the large number of troops needed to protect the settlers.

The murder earlier this year of a 23-year-old student from the Kyryat Arba settlement near Hebron is a case often cited to rebut that particular security argument.

However the case for settlements is argued as opposition to Israel's West Bank policies intensifies, Palestinian leaders say they welcome the change to grapple with the issue on a basis other than religious heritage.

Security guarantees are negotiable, Palentinian leaders frequently say when they talk about the settlement controversy, but biblical rights are harder to deal with at the conference table.