Essentially, there are demonic life activity in this great universe that tries to hinder the True Law, Nichiren Daishonin’s Buppo. Therefore, when a person is practicing the Daishonin’s teaching and is about to change their fate, these evils force will always get in the way.
Without understanding this principle, we might think it would be much easier if there were no such thing as evil obstacles.
Asai Sensei explained it this way:
“For example, groundwater flows under hard bedrock.
When you break through this bedrock, water will gush out.
But if you give up and stop digging, not a drop of water will come out.”
That makes it exciting when you hit solid bedrock, because it’s a sign that groundwater is close by, right?
Without understanding the principle of Three Obstacles and Four Evils, you will miss the chance to change your fate, and will not be able to obtain unbreakable happiness.
“There is always a difference between the ebb and flow of the tide, the rising and setting of the moon, summer and autumn, winter and spring.
This is how an ordinary person becomes a Buddha.
If there are always three obstacles and four evils, the wise will rejoice and the foolish will retreat.”
-Nichiren Daishonin
Unbreakable Happiness 