Technically, it does not seem correct to say Abraham was judged righteous for his willingness to kill his son. Abraham is deemed righteous in virtue of his willingness to trust God—how he was asked to do that is actually beside the point. The real source of the difficulty seems to come out when we consider modern-day scenarios which attempt to mirror this episode: if the mother who drowns her child cannot be excused because of her belief that she was commissioned by God for the task, why is Abraham any different? Presumably, the direct revelation from God that Abraham received was enough to provide him with the certainty that God was indeed the source of the revelation. His great triumph, then, was in trusting that the God he knew was speaking to him knew what he was doing. In the case of modern-day copycats, on the assumption that they are not hearing from God it follows that they would not have received the certainty given to Abraham (and thus they are rightly rendered guilty for acting as though they had).