How Nature confers power

It's practical and commonsensical.

Think how parents confer power to their children.

Would you give matches to a child who has not yet demonstrated the ability to use them appropriately, safely?

You would if he has demonstrated the ability, you have some sense of knowing, some sense of comfort in letting him use the matches. This doesn't mean he always will but nevertheless...

When we start talking about spiritual advancement. Yogic power. Revelation of Nature's mysteries and the granting of her power, it is the exact same thing.

It will only be conferred on the deserving recipient, the one who has demonstrated through the trustworthiness and purity of their character (usually in matters least moments) the ability to receive greater and greater power (usually in the form of wisdom).

Abraham Lincoln once said, "If you want to test a man's character, give him power."

Nature, though, tests you first before the power is granted.