haniṣyāmi balaḿ hy etad
bhuvi bhāraḿ samāhitam
māgadhena samānītaḿ
vaśyānāḿ sarva-bhūbhujām
akṣauhiṇībhiḥ sańkhyātaḿ
bhaṭāśva-ratha-kuñjaraiḥ
māgadhas tu na hantavyo
bhūyaḥ kartā balodyamam
hanishyami -- I will kill; balam -- army; hi -- certainly; etat -- this; bhuvi -- upon the earth; bharam -- a burden; samahitam -- collected; magadhena -- by the King of Magadha, Jarasandha; samanitam -- brought together; vasyanam -- subservient; sarva -- all; bhu-bhujam -- of the kings; akshauhinibhih -- in akshauhinis; sankhyatam -- counted; bhata -- (consisting) of foot soldiers; asva -- horses; ratha -- chariots; kunjaraih -- and elephants; magadhah -- Jarasandha; tu -- however; na hantavyah -- should not be killed; bhuyah -- again; karta -- he will make; bala -- (to collect) an army; udyamam -- the endeavor.
After due consideration, Lord Krishna decided that since He had descended to the earth to destroy the demons, and since Jarasandha was so enthusiastic to bring all the demons to the Lord's front door, it was definitely more efficient to keep Jarasandha alive and busy.