SB 10.50.47

āvayoḥ yudhyator asya
 yady āgantā jarā-sutaḥ
bandhūn haniṣyaty atha vā
 neṣyate sva-puraṁ balī
Word for word: 
āvayoḥ — the two of Us; yudhyatoḥ — while fighting; asya — with him (Kālayavana); yadi — if; āgantā — comes; jarā-sutaḥ — the son of Jarā; bandhūn — Our relatives; haniṣyati — he will kill; atha — or else; neṣyate — he will take; sva — to his own; puram — city; balī — strong.
Translation: 
“If powerful Jarāsandha comes while We two are busy fighting Kālayavana, Jarāsandha may kill Our relatives or else take them away to his capital.