It means that God's Creation has not its source in any necessity; it comes from his fullness of joy; it is his love that creates, therefore in Creation is his own revealment.
We try to realize the essential unity of the world with the conscious soul of man; we learn to perceive the unity held together by the one Eternal Spirit, whose power creates the earth, the sky, and the stars, and at the same time irradiates our mind.
Joy is there everywhere; it is superfluous, unnecessary; nay, it very often contradicts the most peremptory behests of necessity. It exists to show that the bonds of law can only be explained by love; they are like body and soul. Joy is the realisation of the truth of oneness, the oneness of our soul with the world and of the world-soul with the supreme lover.