John 8:11 - "Neither do I condemn you." - Jesus actually reminds her that the penalty is death. But He is expanding understanding of the OT law.
Maxwell on Deuteronomy - There are 5 different Hebrew words for taking human life. The word used in this commandment is the one which means to take an innocent life either by criminal intent or through negligence. The thrust is that human life is to be valued and protected. It actually calls for us to choose not to take life by criminal intent and to be careful that by our carelessness and negligence, we do not cause the death of another human. (sanctity of life is to be guarded)