Katz threatened, as you can see in the screenshot of his tweet above, that the residents of Iran will soon pay the price for their dictators decision to target civilians in Israel with ballistic missiles aimed at residential neighborhoods.

Understandably Katz has come under a lot of criticism for saying this. Not just from around the world but especially from Israelis. 
I think this might be another case of a bad choice of words but I dont think he meant we are going to target civilians. We dont even do that in Gaza and have no reason to do it in Iran where we know (or at least think) most residents are against the government. He probably means they will pay the price by loss of electricity, the economy collapsing from the oil fields being destroyed and the like.

Politicians really need to choose their words better to make their point. Shoot less from the hip.