Problems come in life just as they do in nature. You cannot stop them but only shield yourself from them. At the same time a state of offense should not be used either.
The character of this poem was in a comfortable and happy state of mind before the wrath of the storm pulled him out of the nirvana. "I leave the book upon a pillowed chair." His mind was engrossed in the book and his body sat pleasantly in the padded chair.
Life may be good it may even be great but there are constantly storm clouds building for the purpose of disrupting our lives. Even if there is foresight to there presence we cannot stop them. "Weather abroad and weather in the heart alike come on regardless of prediction." Predicting what will happen in the future does nothing to stop it from becoming a reality.
The only thing we can do is shield ourselves from it's fury the same way the character shuts the windows, draws the curtains, and lights the candle.
In life the same thing must be done by being protected from any harm the storms of our life may bring about either mental or physical. Some things in life happen no matter what we do or how hard we work to try and thwart it's effort. "The wind will rise, we can only close the shutters." Problems come into every life, how a person deals with it will determine the outcome more than what the original situation was. It is suggested to simply protect oneself from the protagonist rather than becoming one. The character in this poem lights a candle which brings a light glow into the room with some heat as well. That same person does not build a fire as if to consume the troubles that surround it.
We should not distress about the troubles in our life. At the same time a welcome is not needed. Protection from the adversary will promptly bring about the best outcome. Aggression is not essential for a prosperous ending and will likely bring about a worse situation.