Kural - 17

If clouds restrain their gifts and grant no rain,
The treasures fail in ocean's wide domain

Explanation
Even the wealth of the wide sea will be diminished, if the cloud that has drawn (its waters) up gives them not back again (in rain).

Tamil Transliteration
Netungatalum Thanneermai Kundrum Thatindhezhili
Thaannalkaa Thaaki Vitin.