By "we" do you mean the U.S.? What makes you think Obama will commit the U.S. to assist Israel?
If you are Israeli, yes, help from Germany is good but don't expect U.S. involvement, Obama won't allow that.
Doesn't matter if Obama chooses to be involved or not.
The US military will come under attack throughout the Gulf region. Iran will attack Gulf oil fields as well.
If Israel attacks, the US WILL BE INVOLVED and will have to finish it.