Kural - 887

As casket with its cover, though in one they live alway,
No union to the house where hate concealed hath sway

Explanation
Never indeed will a family subject to internal hatred unite (really) though it may present an apparent union like that of a casket and its lid.

Tamil Transliteration
Seppin Punarchchipol Kootinum Kootaadhe
Utpakai Utra Kuti.