SB 10.50.45

taṁ dṛṣṭvācintayat kṛṣṇaḥ
 saṅkarṣaṇa sahāyavān
aho yadūnāṁ vṛjinaṁ
 prāptaṁ hy ubhayato mahat
Word for word: 
tam — him; dṛṣṭvā — seeing; acintayat — thought; kṛṣṇaḥ — Lord Kṛṣṇa; saṅkarṣaṇa — by Lord Balarāma; sahāya-van — assisted; aho — ah; yadūnām — for the Yadus; vṛjinam — a problem; prāptam — arrived; hi — indeed; ubhayataḥ — from both sides (from Kālayavana and also from Jarāsandha); mahat — great.
Translation: 
When Lord Kṛṣṇa and Lord Saṅkarṣaṇa saw Kālayavana, Kṛṣṇa thought about the situation and said, “Ah, a great danger now threatens the Yadus from two sides.
Purport: 

We may note here that although Śrī Kṛṣṇa had defeated Jarāsandha seventeen times against tremendous odds, He did not immediately annihilate the army of Kālayavana, thus keeping intact the benediction granted to Gārgya by Lord Śiva, as explained in the previous purport.