(Mahabharata, Shanti Parva 318-21-13)
A friend is a friend only when he is faithful and trustworthy.
#Sanskrit
(Abhignana Shakuntalam)
Friendship beyond limits should be ominous of some guilt to take place ahead.
#Sanskrit
कारणेन हि जायन्ते मित्राणि रिपावस् तथा
(सुभाषित रत्न भंडागार)
No one is no one's friend. No one is no one's enemy. Friendship and enemity happen for certain reasons.
#Sanskrit