Would you ever kill an innocent kid just because your commander asks you to ?
First I want to clarify that since I was not in a combat position during my service I would never be faced with this kind of dilemma.
Second, the over rule in the IDF, and for most armies for that matter, is that when you receive an order from the commanders above you, you should obey, and moreover, you should follow it the best way you can.
However, and this is a very big however, some orders should not be followed. These are referred to as “manifestly illegal order”- an order that is clearly an illegal order (such as the one you stated above) and following it will be considered a criminal offense. A soldier who has been granted with such an order possesses the responsibility to disobey that order. In the case when he chose to follow a “manifestly illegal order” he will be brought to justice according the the Israeli law system and face the consequences and the necessary punishment of him crime.
I want to state that the IDF values human life and that I had never heard of such an order given to anyone. Still to answer your question, such an order is illegal and I would not have obeyed it.