Comparison of Form (Hebrew: Hashva'at Tzura, השוואת צורה)
There is matter, and there is form. The matter is the body—or anything physical. The form is the inner quality of behavior: the soul, the desire, the thoughts.
For example: The man is a hero. The man is the matter. "Hero" is the form.
Desire, thought, and emotion is its inner form. There is a rule that applies to all realms (or "worlds"): for things to connect, they must be similar. If we want two entities to connect, there must be resemblance between them. This resemblance is called Comparison of Form meaning similar desires, similar thoughts.
For example: A husband and wife who want to live in love. One wants X, and the other wants Y. One of them must change their desire for the sake of the other. The husband thinks, "We'll do what you want; we won't do what I want." He aligns his desire with hers, and they become one desire. As a result, they get along and live in love.
When there is one desire, we become one. This connection is called love. In Hebrew, the word "love" (Hebrew "אהבה" "Ahava") has the same numerical value (Gematria) as the word "one" (Hebrew "אחד" "Echad").
To reach the truth—and through it, attain happiness—one should practice Comparison of Form with the Source, with God.
The way to come closer to God is by becoming similar to Him: by learning to love unconditionally, to forgive completely, and to help others without thinking of personal benefit—focusing only on how it may benefit others.