Did you tear his heart...

It is narrated on the authority of usama b. Zaid that the Messenger of allah (may peace be upon him) sent us in a raiding party. We raided Huraqat of Juhaina in the morning. I caught hold of a man and he said: there is no god but allah, I attacked him with a spear. It once occurred to me and I talked about it to the apostle (may peace be upon him). The Messenger of Allah (may peace be upon him) said: Did he profess "there is no god but allah," and even then you killed him? I said: Messenger of allah, he made a profession of it out of the fear of the Weapon. He (the Holy Prophet) observed: Did you tear his heart in order to find out whether it had professed or not? and he Went on repeating it to me till I wished I had embraced Islam that day. (Sahih Muslim, Book #001, Hadith #0176)

I don't know but this hadith keeps haunting me. The words 'did you tear his heart in order to find out' keep repeating, keep reverberating. They make me question my judgments about people every day, every time.