(NH14)Adultery when married, apostates and eye for an eye
On the authority of Ibn Mas'ud (may Allah be pleased with him), who said: The Messenger of Allah* said:

The blood of a Muslim may not be legally spilt other than in one of three (instances) : the married person who commits adultery; a life for as life: and one who forsakes his religion and abandons the community.

It was related by al Bukhari and Muslim.