There are many dangers surrounding Israel. It's almost hard to pick the worst one. The biggest for Defense Minister Ehud Barak is that old ancient kingdom, Persia, which today is called Iran. It is the biggest because they are able to manipulate the system and are about to obtain nuclear weapons. Of course, who else would they use such weapons on? They've threatened Israel so many times already.
The USA is also in harm's way. Iran is getting away with disobeying the Security Council decisions and directives from the International Atomic Energy Agency. As they see they can get away with moving toward military nukes, they will just keep on going. North Korea and Pakistan have nuclear weapons now, even though they had tough sanctions. Where's the reason to stop Iran from doing so?
Israel can't afford a lot of time for the world to decide to act and prevent Iran from reaching this destructive goal. The longer they wait, Iran will have the time to finish the job. Israel would like to see world cooperation in working on a solution and they feel all options are on the table. Israel and Egypt have had good relations ever since Sadat came to Israel and made peace. Mubarak was able to continue that relationship. Now that the Muslim Brotherhood is stepping into power, that peace is on the line. They have just had a commercial dispute over their gas supply agreement with Israel. Usually, trade or business between two countries can keep them on a peaceful relationship. I hate to see this happen.