Friends should be well tried. Enemies also should be well studied. In this world, a task like this is considered by even the learned as a difficult one requiring sharp intelligence.
वेदितव्यानि मित्राणि विज्ञेयाश्चापि शत्रवः। एतत् सुसूक्ष्मं लोकेऽस्मिन् दृश्यते प्राज्ञसम्मतम्॥