Kural - 625

When griefs press on, but fail to crush the patient heart,
Then griefs defeated, put to grief, depart

Explanation
The troubles of that man will be troubled (and disappear) who, however thickly they may come upon him, does not abandon (his purpose).

Tamil Transliteration
Atukki Varinum Azhivilaan Utra
Itukkan Itukkat Patum.