Ibnul-Qayyim رحمه الله said:
Beware of falsehood because it spoils your natural ability to gain
information, and it spoils your information and your ability to teach people. The liar describes
that which does not exist, and that which exists he says it does not exist just
as he describes truth as falsehood and falsehood as truth, and good as evil and
evil as good. It spoils his conception and his knowledge, which then becomes
a punishment. Then he describes what is not true to the person who trusts
him. The heart of a liar is far removed from the
truth, and is inclined to that which does not exist and he prefers falsehood.
When his ability to perceive has been spoiled as well as his knowledge, which
is the basis of every voluntary deed, these deeds would also be spoiled and the
principle of falsehood would come into force.
