"An earthquake is shaking the whole Arab world and a large part of the Muslim world and we don't yet know how these things will turn out," the premier said at a swearing-in ceremony for new army chief Major General Benny Gantz.
"We are ready for all eventualities because we know that the foundation of our existence, and our capacity to convince our neighbours to live in peace with us, is based on the Israeli army," he said during a ceremony at his Jerusalem office.
Gantz takes over the post as Israel's strategic stance in the Middle East undergoes a shakeup in the wake of a popular revolt in Egypt which ousted president Hosni Mubarak after three decades in power.
Israel has reacted cautiously to the overthrow of Mubarak, an ally who was involved in years of Middle East peace negotiations.
But it welcomed a statement by Egypt's new military ruling council that Cairo remains committed to all its treaties, including its landmark 1979 peace deal with Israel.