The Creator desires for us to receive pleasure from Him. This is the plan of creation. Since He is Good and Does Good, the only thing He lacks is someone to do good upon. That is why He created us out of a material called "the will to enjoy."
But what should we enjoy? Precisely Him. When our desire feels that the Creator is close, that He fulfills it and is united with it, it experiences pleasure. On the other hand, when it grows distant from the Creator, it feels worse in relation to Him to the point that is suffers and feels empty. Yet we always feel only the Creator!
Our material is sensitive to the Creator’s sensation and presence. If it feels the Creator more, it perceives Him as pleasure, and if it feels Him less, it perceives Him as suffering. This happens until the will to enjoy the Creator grows more and more distant from Him, finally reaching a state of completely losing all contact with Him. Then the will to receive pleasure finds itself in this world, where there is no connection with the pleasure or its source.
This separation is necessary so we would desire to unite with Him and enjoy Him of our own accord, and to understand that there is nothing sweeter and better than being unified with Him. This mutual action is called "Zivug" (spiritual unity), when we become included into each other to such an extent that it is impossible to distinguish and separate us from each other. That is the unity we have to reach. And if we acquire the right necessity for this, then we will begin to feel Him, unite with Him, and feel His embrace.
From the lecture on 11/2/10