Kural - 664

Easy to every man the speech that shows the way;
Hard thing to shape one's life by words they say

Explanation
To say (how an act is to be performed) is (indeed) easy for any one; but far difficult it is to do according to what has been said.

Tamil Transliteration
Solludhal Yaarkkum Eliya Ariyavaam
Solliya Vannam Seyal.