Answer by taking a quote from the following article:

Menachem Begin ( listen ; Hebrew: m@nakhem be'giyn Menahem Begin, Polish: Mieczyslaw Biegun; Russian: Menakhem Vol'fovich Begin Menakhem Volfovich Begin; 16 August 1913 - 9 March 1992) was an Israeli politician, founder of Likud and the sixth Prime Minister of Israel.

In 1978 Begin, aided by Foreign Minister Moshe Dayan and Defense Minister Ezer Weizman, came to Washington and Camp David to negotiate the Camp David Accords, leading to the 1979 Egypt-Israel Peace Treaty with Egyptian President, Anwar Sadat. Before going to Washington to meet President Carter, Begin visited Rabbi Menachem M. Schneerson for his advice. Under the terms of the treaty, brokered by US President, Jimmy Carter, Israel was to hand over the Sinai Peninsula in its entirety to Egypt. The peace treaty with Egypt was a watershed moment in Middle Eastern history, as it was the first time an Arab state recognized Israel's legitimacy whereas Israel effectively accepted the land for peace principle as blueprint for resolving the Arab-Israeli conflict. Given Egypt's prominent position within the Arab World, especially as Israel's biggest and most powerful enemy, the treaty had far reaching strategic and geopolitical implications.  Almost overnight, Begin's public image of an irresponsible nationalist radical was transformed into that of a statesman of historic proportions. This image was reinforced by international recognition which culminated with him being awarded, together with Sadat, the Nobel Peace Prize in 1978.  Yet while establishing Begin as a leader with broad public appeal, the peace treaty with Egypt was met with fierce criticism within his own Likud party. His devout followers found it difficult to reconcile Begin's history as a keen promoter of the Greater Israel agenda with his willingness to relinquish occupied territory. Agreeing to the removal of Israeli settlements from the Sinai was perceived by many as a clear departure from Likud's Revisionist ideology. Several prominent Likud members, most notably Yitzhak Shamir, objected to the treaty and abstained when it was ratified with an overwhelming majority in the Knesset, achieved only thanks to support from the opposition. A small group of hardliners within Likud, associated with Gush Emunim Jewish settlement movement, eventually decided to split and form the Tehiya party in 1979. They led the Movement for Stopping the Withdrawal from Sinai, violently clashing with IDF soldiers during the forceful eviction of Yamit settlement in April 1982. Despite the traumatic scenes from Yamit, political support for the treaty did not diminish and the Sinai was handed over to Egypt in 1982.  Begin was less resolute in implementing the section of the Camp David Accord calling for Palestinian self-rule in the West Bank and Gaza Strip. He appointed Agriculture Minister Ariel Sharon to implement a large scale expansion of Jewish settlements in the Israeli-occupied territories, a policy intended to make future territorial concessions in these areas effectively impossible. Begin refocused Israeli settlement strategy from populating peripheral areas in accordance with the Allon Plan, to building Jewish settlements in areas of Biblical and historic significance. When the settlement of Elon Moreh was established on the outskirts of Nablus in 1979, following years of campaigning by Gush Emunim, Begin declared that there are "many more Elon Morehs to come." During his term dozens of new settlements were built, and Jewish population in the West Bank and Gaza more than quadrupled.

What else can you tell me about the treaty?
Yet while establishing Begin as a leader with broad public appeal, the peace treaty with Egypt was met with fierce criticism within his own Likud party.