Kural - 589

One spy must not another see: contrive it so;
And things by three confirmed as truth you know

Explanation
Let a king employ spies so that one may have no knowledge of the other; and when the information of three agrees together, let him receive it.

Tamil Transliteration
Otrer Runaraamai Aalka Utanmoovar
Sotrokka Therap Patum.