Is it permissible to lie if it would protect a Muslim from being killed?

Lying is fundamentally forbidden, but it may become permissible or even obligatory. If it's possible to avoid it through tawriyah (ambiguous speech), that is preferable. It has been authentically reported from Umar and Imran ibn Husayn that they said: "In ambiguous speech, there is room to avoid lying." If a Muslim's life is inviolable ( عصوم الدم), then lying to save him from being killed is obligatory.