If we merely compare something we will get identities. This leads to dialectics. This distinguishes the classical logic from dialectical logic. Sometimes Hegel emphasizes that he searches merely necessities. If we recognize the relations of Something and its Other, we recognize the essence too.
Relations are the permanence in the proceeding Some-things.
Essence represents itself as relation. In this sense cognition is cognition of the essence, i.e. essential relations. These relations must reflect the inner contradictories. All development is founded in these contradictions. Of course developing things and outer conditions imply and entail the course of development.