Teachings on Hypocrisy (insincerity by virtue of pretending to have qualities or beliefs that you do not really have) in Bhagavad Gita
Hypocrisy, arrogance and self-conceit, anger, and also harshness and ignorance, belong to one who is born, O Partha, for a demoniac-Estate. (Chapter 16 verse 4)
Filled with insatiable desires, full of hypocrisy, pride and arrogance, holding evil ideas through delusion, they (the ignorant) work with impure resolves. (Chapter 16 Verse 10)
Those men who practice terrific austerities, not enjoined by the scriptures, given to hypocrisy and egoism, impelled by the force of lust and attachment . . .
Senselessly torturing all the elements in the body, and Me also who dwells within the body --- you may know these to be of 'demoniacal' resolves. (Chapter 17 Verse 5 and 6)
The austerity which is practiced with the object of gaining good reception, honour and worship, and with hypocrisy, is here said to be Rajasic, unstable, and transitory. (Chapter 17 Verse 18)