(His Divine Grace A.C. Bhaktivedanta Swami Prabhupada)
"A person who knows what is spiritual and what is material and who is firmly fixed in the spiritual position can be jagad-guru, the spiritual master of the entire world. One cannot become jagad-guru simply by advertising oneself as jagad-guru without knowing the essential principles for becoming jagad-guru. Even people who never see what a jagad-guru is and never talk with other people become puffed-up sannyāsīs and declare themselves jagad-gurus. Śrī Caitanya Mahāprabhu did not like this. Any person who knows the science of Kṛṣṇa and who is fully qualified in spiritual life can become jagad-guru."