Vidur was a very wise man in Indian history and a Prime Minister of Pandavs and Kauravs. Vidura is held to be a paragon of truth, dutifulness, impartial judgement and steadfast dharma. He is considered the embodiment of the inner consciousness of the Mahabharata. The following is his advice on how to recognize a true friend.
“He is not friend whose anger inspires fear, or who is to be waited upon with fear. He, however, on whom one can repose confidence as on a father, is a true friend. Other friendships are nominal connection. He that bears himself as a friend, even though unconnected by birth of blood, is a true friend, a real refuge, and a protector.
He, whose heart is unsteady, or who does not wait upon the aged, or who is of a restless disposition cannot make friends. Success (in the attainment of objects) forsakes the person whose heart is unsteady, or who has no control over his mind, or who is a slave of his senses, like swans forsaking a water tank whose waters have dried up. They that are of weak minds suddenly give way to anger and are gratified without sufficient cause; they are like clouds that are so inconstant.
The very birds of prey abstain from touching the dead bodies of those who having been served and benefited by friends, show ingratitude to the latter. Be thou poor or be thou rich, thou should honour thy friends. Until some service is asked, the sincerity or otherwise of friends cannot be known.”