A leader must be peaceful, self-controlled, austere, pure, tolerant, honest, wise, learned and religious.
His Divine Grace A.C. Bhaktivedanta Swami Prabhupada
In his letter to Karandhara, 27th July, 1973.
By rendering devotional service unto the Supreme Personality of Godhead, Sri Krishna, one immediately acquires causeless knowledge and detachment from the world. If one engages in the service of Vasudeva ,Krishna, this knowledge comes, and one becomes a mahatma. A mahatma is one who realizes that Krishna is everything. He does not defy Krishna or try to become Krishna. One who does so is not a mahatma, but a duratma, a rascal.
His Divine Grace A.C. Bhaktivedanta Swami Prabhupada
In his lecture on Srimad Bhagavatham, 3rd Canto, Chapters 25 through 33.