Bhagavad Gita Chapter 14 Verse 15
भगवद् गीता अध्याय 14 श्लोक 15

रजसि प्रलयं गत्वा कर्मसङ्गिषु जायते।
तथा प्रलीनस्तमसि मूढयोनिषु जायते।।14.15।।



हिंदी अनुवाद - स्वामी तेजोमयानंद
।।14.15।। रजोगुण के प्रवृद्ध काल में मृत्यु को प्राप्त होकर कर्मासक्ति वाले (मनुष्य) लोक में वह जन्म लेता है तथा तमोगुण के प्रवृद्धकाल में (मरण होने पर) मूढ़योनि में जन्म लेता है।।


Kumara Vaishnava Sampradaya - Commentary
Now Lord Krishna describes that when a jiva or embodied being dies while  in
raja guna or the mode of passion one takes birth  among  those  who  perform
activities out of desire for rewards and  having  been  born  as  such  will
endeavour mightily to accomplish works that would  be  rewarded  by  immense
wealth and power even up unto the heavenly spheres. Similarly  if  one  dies
while under the influnce of tama guna or the mode  of  ignorance  then  such
jivas will be born from the wombs of animals such as  pigs  and  dogs  where
one would be completely incapacitated to perform  any  activity  that  would
give any spiritual benefit.