It is not that Radharani is separate from Krsna. Radharani is also Krsna, for there is no difference between the energy and the energetic. Without energy, there is no meaning to the energetic, and without the energetic, there is no energy. Similarly, without Radha there is no meaning to Krsna, and without Krsna there is no meaning to Radha. Because of this, the Vaisnava philosophy first of all pays obeisances to and worships the internal pleasure potency of the Supreme Lord. Thus the Lord and His potency are always referred to as Radha-Krsna. Similarly, those who worship Narayana first of all utter the name of Laksmi, as Laksmi-Narayana. Similarly, those who worship Lord Rama first of all utter the name of Sita. In any case — Sita-Rama, Radha-Krsna, Laksmi-Narayana — the potency always comes first.

From Srila Prabhupada’s introduction to Sri Caitanya-caritamrta