Surah 103: The Declining Day (Al-'Asr):
103.001 By the declining day,
103.002 Lo! man is a state of loss,
103.003 Save those who believe and do good works, and exhort one another to **
truth
**
and exhort one another to endurance.
The first line of the next chapter:
104.001 Woe unto every slandering traducer,
Also: Truth is a name of Allah:
If someone wants to kill a Muslim’s family, the Muslim is permitted to lie to save them - otherwise the Muslim would be compelled by God to be as honest as possible, which in that case isn’t a good idea.
Do not slander.