The red light and the green light

I have two intimate friends:
The red light
The green light.

The red light warns me
    And cautions me
    And finally commands,

The green light inspires me
    And encourages me
    And finally whispers,

My red friend
    Teaches me patience.
My green friend
    Teaches me dynamism.

My red friend tells me
    My life is precious.
My green friend tells me
    My goal is precious.

My red friend
    Perfects my will.
My green friend
    Fulfils my dream.