Here's some more,
"The moment a man talks to his fellows he begins to lie" Hilaire Belloc-The Silence of the Sea
"Nobody speaks the truth when there's something they must have" Elizabeth Bowen(1899-1973)-The House in Paris
"It is hard to believe that a man is telling the truth when you know that you would lie if you were in his place"H.L Mencken-Prejudices
"He who does not need to lie is proud of not being a liar"Nietzsche-Nachgelassene Fragmente
"You can fool some of the people all of the time and all of the people some of the time; but you can't fool all the people all the time"Abraham Lincoln
"You can fool too many of the people too much of the time"James Thurber-The Owl Who Was God
"Almost every man wastes part of his life in attempts to display qualitites which he does not possess, and to gain applause which he cannot keep"Samuel Johnson-The Rambler
"He led a double life. Did that make him a liar? He did not feel a liar. He was a man of two truths" Iris Murdoch-The Sacred and Profane Love Machine
"That a lie which is all a lie may be met and fought wih outright, but a lie which is part truth is a harder matter to fight." Lord Tennyson-The Grandmother
"A truth that's told with bad intent beats all the lies you can invent" William Blake-Auguries of Innocence
"You can only find truth with logic if you have already found truth without it" G.K. Chesterton -The Man who was Orthodox
Wolfy