In Islam, lying or omissions for the 'greater good,' according to a strict or radical Islam/Islamist philosophy is not only acceptable, it is holy and blessed work. It is called al-Takeyya (or al-Taqiyya) and is a strategy outlined in the Hadiths and supported by various interpretations of some of the Suras in the Koran.
Could the angel that appeared to Mohammed have been the Father of Lies?
It really was not an angle but in fact it was a goat that he had a love affair with.