I’ve followed Israel since the 1970s and visited there recently. While I wouldn’t say Israel isn’t afraid of Iran (you’ll get a lot of variance in attitudes among 8.7 million people, even in their government), I think they take the threat seriously and act accordingly.
Israel has some of the best intelligence services in the world. When it comes to Iran I would guess they have better intelligence than any other nation including the USA and Russia. This is due to their reliance on physical assets – people – as opposed to intercepted communications provided through technology which the US and other services prefer. My guess – and it’s just that – is that they have assets in place through all levels of the government and military and as a result know pretty much everything they need to know.
One of the things they understand is when their enemies are mouthing off and when they are serious. This can usually be determined by the person making the statement, his position, and his support. They can then run that statement against the overall picture provided by their tens of thousands of assets. In this case I’d say this particular commander is just “playing to the crowd.”
Living in a bad neighborhood gives you a different perspective, which is why I don’t trust American or European pronouncements on Israel and its neighbors.