What does Islam say about hypocrisy?

During the time of Rasulullah (Sallallaahu Alayhi Wasallam), there were
Munafiqeen (hypocrites). They used to claim to be Muslims but had Kufr in
their hearts. They hated Islam and the Muslims and their endearvour was to
damage Islam from within. Allah Ta'ala says, 'Verily the Munafiqeen will be
in the lowest pitch of the fire.'

Rasulullah (Sallallaahu Alayhi Wasallam) said, 'The signs of a Munaafiq are
three: When he speak, he speak lies; When he promises, he breaks it and when
he is entrusted, he embezzles.' (Mishkaat)

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai
FATWA DEPT.