Subhadra is yogamaya. The spiritual energy is called yogamaya. And she has 16 different expansions. Out of these 16 expansions, Subhadra is one. The mahamaya of the material energy is also expansion of the energy of yogamaya; and both yogamaya and mahamaya are equally important to Krishna as much as any government department is equally important for functioning of the government.
Letter to Madhusudana, 29 July, 1968