SB 10.71.6
dvai-rathe sa tu jetavyo
ma sataksauhini-yutah
brahmanyo ’bhyarthito viprair
na pratyakhyati karhicit
Translation:
He will be defeated in a match of single chariots, not when he is with his hundred military divisions. Now, Jarasandha is so devoted to brahminical culture that he never refuses requests from brahmanas.
Purport:
It might be argued that since only Bhima could equal Jarasandha in personal strength, Jarasandha would be more powerful when supported by his huge army. Therefore, Uddhava here recommends single combat. But how could Jarasandha be persuaded to give up the support of his powerful army? Here Uddhava gives the clue: Jarasandha will never refuse a request from brahmanas, since he is devoted to brahminical culture.