Every person is a rightful heir to the Truth. But he who would inherit it must be spiritually prepared for it, and this spiritual preparation sometimes takes several lives of patient and persistent effort. Therefore, one  of the first requirements of the aspirant is that he should combine unfailing enthusiasm with unyielding patience. Once an individual is determined to realize the Truth, he finds that his path is beset with many difficulties, and there are very few who persist with steady courage till the very end. It is easy to give up the effort when one is confronted with obstacles.
This might be illustrated by a story of a man from Poona, India. He once read a spiritual book that impressed him so deeply that he felt like renouncing everything. He left Poona and went to a forest near the city; and sitting under a tree with prayer beads in his hand, he began to repeat God’s name. He kept doing this all day in spite of much inconvenience and dwindling enthusiasm. After sunset he heard from all sides the cries of animals; and though these cries grew louder and louder in the gathering darkness of the night, he persisted in his determination. However, when he saw through the darkness a huge bear coming toward him, he fled for his life and ran at top speed until he fell unconscious in a shop back in Poona. As he regained consciousness, he related his adventure to those who had gathered around him, much to their amusement-and that finished his mood for renunciation.
-Discourses 7th Ed. p355