Kural - 461

Expenditure, return, and profit of the deed
In time to come; weigh these- than to the act proceed

Explanation
Let a man reflect on what will be lost, what will be acquired and (from these) what will be his ultimate gain, and (then, let him) act.

Tamil Transliteration
Azhivadhooum Aavadhooum Aaki Vazhipayakkum
Oodhiyamum Soozhndhu Seyal.