Iran is a major concern for Israel. In the past, Arab states played that role.
This week marks 49 years since the 1967 war. Arab states wished to wipe out Israel, based on their traditional ambition. It is not certain whether Arab leaders wanted war in 1967. Arab media announcements at that time should be separated from the realistic approach of Arab leaders regarding their actual military capabilities. Nevertheless, Israel felt then that it faced a clear and present danger, which drove the country to launch a preventive war.
The PLO conducted assaults against Israel in the years before the 1967 war, which contributed to the tension that led to the 1967 showdown. The PLO hoped that Arab militaries would fight Israel. The PLO got their wish but not the outcome they were looking for, to say the least. See more in my new book: Israel’s way of War: A Strategic and Operational Analysis, 1948–2014 (Jefferson NC: McFarland 2016).
In the past decade, Israel developed security cooperation with the PA in the West Bank against other Palestinians, mostly Hamas. The latter is based mostly in the Gaza Strip. Hamas has ties to Iran. As in 1967, Israel might have to seize all the Gaza Strip if Hamas decides to provoke Israel too much.
In 1967 Egypt challenged Israel directly by deploying around 100,000 troops in the Sinai Peninsula. Now the Egyptian military has been fighting about a thousand ISIS fighters in Sinai, a struggle that obviously serves an Israeli interest. Therefore, Israel has been cooperating with Egypt against ISIS.
In 1967 Israel seized the Golan Heights. Before the war, Israeli civilians who lived near the Golan Heights were often under fire. Since 2011 the 20,000 Israelis who reside in the Golan Heights have been under some threat too. The civil war inside Syria might spill over into the Golan Heights, i.e., groups like ISIS near the border might turn against Israel. Meanwhile, the different sides in Syria are busy fighting with each other. One of them is Assad, who is backed by Iran.
Hezbollah, an Iranian protégée, did not exist in 1967 since it was created only in the early 1980s. Now this powerful Lebanese group possesses about 150,000 rockets aimed at Israel. Lebanon, which in 1967 was not even a frontline, has become the most serious threat Israel faces.
All in all, in 1967 Israel had to deal with Arab states particularly Egypt, Syria and Jordan. Now Israel has new enemies, non-Arab ones like Iran and Arab groups like ISIS and Hezbollah.