How can love exist between two human beings? An old sage explained that for this to happen people have to be similar in their properties. The universal law is effect in the entire Universe, in all the worlds, including ours; it is called the law of equivalence of form. According to this law, I sense, perceive, and comprehend only the things that are common between me and the object that I investigate, perceive, and observe. If no common property exists between a certain object and me, I am unable to sense it. If there is no commonality in thought – at least, minimal or partial – between another human being and me, I am unable to understand him or her.
When I establish a connection with someone, I understand the person to the measure of the equivalence of form in our desires and thoughts (it must happen both in mind and heart). It can also happen that even if I understanding someone, I draw away, but still there is a certain connection between us. Equivalence of form is a condition for establishing a connection to someone or something.
http://www.youtube.com/watch?v=JFWPeVfWB9o