Shimon Peres has passed away and, with him, the last embodiment of Israel’s great founding generation.

When Peres and his family immigrated to British Mandate Palestine in 1934, Hitler was consolidating his power in Germany, and Europe was about to begin the most shameful chapter of its history. Peres lost many family members, including his grandparents, in the Holocaust. His life’s work — over six decades of public service to the nation state of the Jewish people — was dedicated to ensuring that such a tragedy could never be repeated.

Perhaps more than anyone else, Peres is responsible for ensuring Israel’s security by shaping a powerful and effective defense apparatus that allowed Israel to stand up to its more powerful and populous neighbors. In 1947, when he joined the Haganah — the predecessor to the Israeli Defense Forces — Israel was surrounded by hostile armies intent on its destruction. Jerusalem was under siege by the Arab “Holy War Army,’’ and Jewish kibbutzim were being attacked across Galilee and Samaria.

During those early days, when the very survival of the Jewish state seemed improbable, David Ben-Gurion appointed Peres to secure weapons for Israel from the United States and Europe. He was so successful in this task that, after the War of Independence, he was delegated to the naval services, where his primary task was again to ensure that the Israeli army would be properly equipped if the conflict with its Arab neighbors were to resume. His tireless negotiations with American, French, and British officials led to the signing of several major arms deals and cemented Israel’s status as the foremost military power in the Middle East. At age 29, Peres became director general of the Ministry of Defense. He used that position to develop Israel’s nuclear arsenal, its navy, and its military industrial capacity.

But Peres also understood the Biblical verse “to everything there is a season.’’ Much as he zealously sought to ensure Israel’s security, he was also uncompromising in his quest for peace with its neighbors. When Israel became strong enough to defend itself, Peres saw a change in the seasons, and he became one of the leading voices for reconciliation with Israel’s erstwhile regional enemies. As defense minister, he oversaw the Israeli disengagement from Sinai that paved the way for the peace settlement with Egypt. As foreign minister, he was one of the primary visionaries behind the Israeli-Jordanian Peace Treaty of 1993.

He was also the first prominent Israeli politician to recognize the reality that a demilitarized Palestinian state would not only be just for the Palestinians, but would also be good for the Israelis. His work alongside his great political rival, Yitzhak Rabin, to achieve a lasting solution to the Israeli-Palestinian conflict, at the 1993 Oslo accords, won him a Nobel Peace Prize, and it remains an enduring, if unfinished, chapter of his legacy.

Peres was both a man of principle and of pragmatism. He understood that morality, without the strength to defend it, might cause a repetition of the disaster the Jewish people faced during the 1930s and 1940s, when they lacked the strength to defend themselves against powerful forces intent on their destruction. As prime minister, he did not hesitate to airlift thousands of Ethiopian Jews to Israel when they were threatened with annihilation by the rise of a nationalistic military dictatorship. He showed similar resolve when arguing powerfully for the military raid on Entebbe, Uganda, that rescued over 80 hostages taken by Palestinian terrorists.

But he also understood that strength alone was not enough. For him, Israel’s founding vision was a “country living in peace and security in its homeland and among its neighbors.’’ As he said in a speech he delivered on his 90th birthday: “We long for peace with our neighbors. The yesterday between us and the Palestinians is full of sadness. I believe that the Israel of tomorrow and the Palestine of tomorrow can offer our children a ray of hope. The advancement of peace will complete the march of Israel towards the fulfillment of its founding vision.’’ And while his dream of a two-state solution was never closer than at Oslo in 1993, his tireless work toward that end speaks volumes of the man.

I knew him for 46 years, ever since I interviewed him in Israel for PBS in 1970, and I visited him on almost every trip to Israel. Our last time together in the United States was at a state dinner at the White House for his 90th birthday. He was at the top of his game. As President Obama observed when he awarded Peres the Medal of Freedom in 2012: “In him, we see the essence of Israel itself — an indomitable spirit that will not be denied.’’

Alan M. Dershowitz is professor emeritus of law at Harvard University.