Thriukkural says that one must always speak the truth and should in their mind know something is a lie, they must not speak on it.
For further reading check the following articles:
|100 Differences Between Articles||UPSC Prelims|
|NCERT Medieval Indian History Notes UPSC||UPSC Mains Questions (2013-2019)|
|NCERT Ancient Indian History Notes UPSC||NCERT Modern Indian History Notes UPSC|