Often, when we hear of how men have become sages, it seems as if the decision to give up worldly life was a sudden decision. But there is nothing sudden about the decision.
A person who becomes a sage would have veered more and more towards spirituality in his previous births. The present birth is when the spiritual tendency is at its peak, and when the right moment arrives, the person renounces worldly life and takes to sanyasa.
It is a gradual process that does not even begin in the particular birth wherein the renunciation takes place; it is a process that would have begun in a previous birth, said Tiruppur Krishnan, citing an example to explain the idea.
When milk is heated, sometimes it seems to us that it is taking a long time to boil. We think we could step out for just a second to attend to some other errand. Just when our back is turned, the milk boils over, and we remark: “The milk boiled in a second.” This is an inaccurate observation. The milk has been over the flame for some time, and the process of heating reached its culmination when we were not watching. Likewise, though it seems great men suddenly decide to become sanyasis, this is not the case; they have been spiritually inclined since a previous birth. And the ripe moment for renunciation has arrived in this birth.
A man who becomes a sanyasi must be one who has gnana. He who takes to sanyasa because he is upset with someone will never be a proper sanyasi. Ramakrishna Paramahamsa told the story of a man who fought with his wife and said he was going to become a sanyasi and left for the forest. His wife followed him and told him that she, too, was going to become a sanyasi. As they walked, the man noticed a diamond on a river bank; afraid that his wife might be tempted to possess it, he pushed some sand with his feet over the diamond. His wife asked him why he did so. He explained that it was to keep her from temptation. She said that if he had truly been a sanyasi, he would not even have noticed the difference between the sand and a diamond. Since he had, he could not be considered a sanyasi.