Bhagavad Gita Verse 14, Chapter 14

yada sattve pravriddhe tu pralayam yaati dehabhrita |
tadottamavidaan lokaanamalaanpratipadyate || 14 ||
 
When sattva is predominant, and the body dweller reaches his end, then he attains the immaculate worlds of the knowers of the highest.
 
yada : when
sattve : sattva
pravriddhe : predominant
tu : and
pralayam : end
yaati : reaches
dehabhrita : body dweller
tadaa : then
uttamavidaan : knowers of the highest
lokaan : worlds
amalaan : immaculate
pratipadyate : attains
 
Now, Shri Krishna explains the effects of each gunaa from the perspective of reincarnation. He says that one whose mind is in a sattvic state during the time of death travels to realms that are subtler than the human world. These realms are termed as “Brahmaloka”, the abode of Lord Brahma. It is said that there is no room for any desire, sorrow or disease in such realms, given the complete absence of rajas or tamas. Such people, however, are still subject to the bondages caused by sattva, as discussed previously.
 
Let us revisit the example of the young child who has developed a strong identification with a television character played by the actor “ABC”. ABC’s run as an action hero in a popular TV show has ended. He has decided to play the role of a serious professor in his new TV series. The young child now has a choice. He can either continue to identify with ABC in his new role as a professor, or find another TV show with an action hero to identify with. The choice depends on the young child’s mental state. If it is heavily rajasic, he will find another action hero. If it has some sattva, he will follow ABC as a professor.
 
Similarly, our desires and thoughts, which are driven by the gunaas that influence us, will determine our fate after this physical body drops. The subtle body, which is nothing but our desires and thoughts, will attract another physical body that enables it to carry out those desires. It is almost similar to DNA shaping a body based on the programming it contains. Therefore, if our subtle body harbours sattvic thoughts, it will gain entry into a highly sattvic body after death. But if it continues to harbour rajasic or tamasic thoughts, it will obtain a different destination. This is explained in the next shloka.