Answer
The Srimad-Bhagavatam explains that a pure devotee actually begins to enter the spiritual world even before leaving the material body.
Entry into the spiritual world does not occur through the gross physical body.
Every living being, whether a devotee or a non-devotee, must eventually leave the gross body behind. Therefore, no one enters the spiritual world with the material body.
Nor does one enter with the subtle body, consisting of the mind, intelligence, and false ego. Although subtler than the physical body, it is still material and therefore unsuitable for spiritual existence.
The spiritual world is entered through pure consciousness.
When one becomes completely free from identification with both the gross and subtle bodies and becomes fully absorbed in devotional service, one's consciousness is situated in the spiritual realm.
For example, when a devotee chants the Hare Krishna maha-mantra with complete absorption, his consciousness is with Krishna.
At that moment, although physically present in this world, he is spiritually situated in Krishna's eternal abode.
As one's spiritual realization deepens, this experience becomes increasingly complete.
An advanced devotee no longer depends on the material senses for happiness or perception. Instead, spiritual reality is experienced through purified consciousness.
Thus, entrance into the spiritual world is fundamentally a transformation of consciousness through pure devotional service.
Ultimately, when such a perfected devotee leaves the material body, that fully spiritual consciousness naturally carries the soul to Krishna's eternal abode, where eternal loving service to the Lord continues without interruption.
