A man walks up to you and says:
"Everything I say to you is a lie.
Is he telling you the truth or is he lying?
If possible, let the statement made by the man is true. Then, it follows by his own admission, that at least some part of the staement made by him is false. This is a contradiction.
Accordingly, the statement made by the man must be false.
The statement made by the man in this case would imply that some portion inclusive of his statement must contain an element of truth. This is also a contradiction, implying amongst other things, that the statement made by him must be true.
Consequently, we reach a paradox since considering the statement made by the man to be true or false at the outset would imply just the opposite in terms of the texts constituting the man's statement.