By a lie, a man… annihilates his dignity as a man. – Immanuel Kant
but
Truly, to tell lies is not honorable;
but when the truth entails tremendous ruin,
To speak dishonorably is pardonable.
Sophokles
and
Lying increases the creative faculties, expands the ego, and lessens the frictions of social contacts.
Clare Booth Luce
and
People do not believe lies because they have to, but because they want to.
Malcolm Muggeridge
plus
He who speaks the truth must have one foot in the stirrup.
Armenian proverb
and, last but not least
The world desires to be deceived; therefore it is
Petronius (?)