Bhagavad Gita Verse 8, Chapter 15

shareeram yadvaapnoti yachchaapyutkraamteeshvaraha |
griheetvaitaani samyaati vaayurgandhaanivaashayaat || 8 ||
 
When the lord acquires a body, and when he leaves it, he takes them and departs, like the wind takes odours from their seats.
 
shareeram : body
yat : when
avaapnoti : acquires
yat : when
cha : again
api : also
utkraamti : leaves
eeshvaraha : lord
griheetvaitaani : takes them
samyaati : departs
vaayuhu : wind
gandhaan : odours
iva : like
aashayaat : seats
 
Earlier, we saw how the individual soul, the jeeva, wants to interact with Prakriti in order to exhaust its desires. In preparation to do so, it surrounds itself with the mind (which contains the desires) and the five senses. This collection of the jeeva, the mind and the senses is also known as the subtle body, because it is invisible. We can think of the subtle body as a computer file. Just as a computer file needs a computer to express itself, a subtle body needs a physical body to express itself. Whenever the timespan of one human body ends, the subtle body has to find another physical body to continue exhausting its desires.
 
Shri Krishna says that in such a situation, the subtle body, the jeeva with the mind and senses, ejects itself from the physical body and finds another body to settle in. It is similar to a international diplomat who goes from one assignment to another, taking his staff with him wherever he goes. Since the mind and senses follow the jeeva, it is referred to as Ishvara or the lord here, not to be confused with the meaning of Ishvara that has been used throughout the Gita. Once the jeeva finds a new home, it slowly starts unpacking its belongings, the mind and senses, in sequence. It is fascinating to see time-lapse videos of an embryo growing inside a mother's womb. This is the jeeva slowly gaining its faculties, which are nothing but accumulations of additional upaadhis.
 
Imagine that a small wooden box contains a strong perfume. If the box - the seat of the perfume - is opened, the fragrance will slowly start leaving the box and fill the room. Shri Krishna uses this analogy to explain the transfer of the jeeva from one physical body to another. If we bring in the analogy of the eternal essence as space, and combine it with this analogy, we will find that they fit together perfectly. Walls, fragrance, wind, boxes - all these limitations of space are apparent, not real. They are upaadhis, apparent limitations. Space does not care whether we build 2 walls or 2 million walls. No one or nothing can limit space. There is no coming and going of the perfume in space. It is only from a worldly standpoint that the fragrance is moving from the box to the room.