Kural - 881

Water and shade, if they unwholesome prove, will bring you pain
And qualities of friends who treacherous act, will be your bane

Explanation
Shade and water are not pleasant, (if) they cause disease; so are the qualities of (one's) relations not agreeable, (if) they cause pain.

Tamil Transliteration
Nizhalneerum Innaadha Innaa Thamarneerum
Innaavaam Innaa Seyin.