One of the interpretations of the Abraham scenario, according to Jewish thinking, is that Abraham did not argue enough with G-d against killing his son. His faithful obedience to G-d may have been admirable, but his willingness to do something which his conscience told him was very wrong was not so admirable. G-d may have been testing him in this way, as well as teaching him the danger involved in blind obedience without reason. It is also important that Abraham’s wife, Sarah, had no say regarding the killing of her son and was not even informed by her husband. This too was not admirable on Abraham’s part. In short, if G-d put Abraham to the test, Abraham did not pass.
So the answer to your question, in my view, is that if I thought G-d sanctioned my killing of an innocent person, I would have to ask myself several questions, one of which is whether G-d is testing my conscience and faithfulness to Him by NOT listening to what I believe he is telling me to do. Self-defense and wartime killing are another issue, though not for some, for example, Quakers.