Radhashtami day is the most auspicious day of appearance of Goddess of fortune, Sri Radha, who is the feminine counterpart of Lord Sri Krishna.
The scriptures extol her glories as the Supreme mother of the whole universe and the one who mercifully escorts and engages all the jivas in the loving devotional service to Sri Krishna. She always holds a lotus in one of her hands and bestows her blessings out of vaatsalya or motherly affection for the jivas. She is the Supreme shakti of Krishna. Just as sun and sunlight are inseparable, Radha and Krishna are one, but they have separated for the sake of exhibiting unlimited pastimes of love and to expand the bliss of all the jivas who engage in their eternal service. When we approach shakti, with the desire to become shaktimaan and to exploit the material resources, she manifests her anger as Durga with a trident representing threefold miseries (arising from body and mind, other living beings and natural calamities).
But when we approach Shakti with the desire to serve Krishna, the shakti appears as Sri Radha and engages us in the service of the Supreme Lord.
Thus in Bhagavad gita Lord Krishna tells us that we should approach Sri Radha or Lakshmi and take her shelter to learn how to offer devotional service to Supreme Lord. Srila Prabhupada says that one should pray like this: “O Radha! Supreme goddess of fortune! Please accept this flower and offer it to your Krishna”. When one prays so, chanting the holy names of Hare Krishna mantra, one is sure to become free from all impurities of heart and attain the spiritual world to join the eternal service to divine couple.
That world is our real home and this world is a temporary jail meant to reform us. Let us prepare ourselves to return to our eternal home on this auspicious day of Radhashtami! Hare Krishna.