Kural - 796

Ruin itself one blessing lends:
'Tis staff that measures out one's friends

Explanation
Even in ruin there is some good; (for) it is a rod by which one may measure fully (the affection of one's) relations.

Tamil Transliteration
Kettinum Untor Urudhi Kilaignarai
Neetti Alappadhor Kol.