SB 1.10.32

ajāta-śatruḥ pṛtanāṁ
 gopīthāya madhu-dviṣaḥ
parebhyaḥ śaṅkitaḥ snehāt
 prāyuṅkta catur-aṅgiṇīm
Synonyms: 
ajāta-śatruḥ — Mahārāja Yudhiṣṭhira, who was no one’s enemy; pṛtanām — defensive forces; gopīthāya — for giving protection; madhu-dviṣaḥ — of the enemy of Madhu (Śrī Kṛṣṇa); parebhyaḥ — from others (enemies); śaṅkitaḥ — being afraid of; snehāt — out of affection; prāyuṅkta — engaged; catuḥ-aṅginīm — four defensive divisions.
Translation: 
Mahārāja Yudhiṣṭhira, although no one’s enemy, engaged four divisions of defense [horse, elephant, chariot and army] to accompany Lord Kṛṣṇa, the enemy of the asuras [demons]. The Mahārāja did this because of the enemy, and also out of affection for the Lord.
Purport: 

Natural defensive measures are horses and elephants combined with chariots and men. Horses and elephants are trained to move to any part of the hills or forests and plains. The charioteers could fight with many horses and elephants by the strength of powerful arrows, even up to the standard of the brahmāstra (similar to modern atomic weapons). Mahārāja Yudhiṣṭhira knew well that Kṛṣṇa is everyone’s friend and well-wisher, and yet there were asuras who were by nature envious of the Lord. So out of fear of attack from others and out of affection also, he engaged all varieties of defensive forces as bodyguards of Lord Kṛṣṇa. If required, Lord Kṛṣṇa Himself was sufficient to defend Himself from the attack of others who counted the Lord as their enemy, but still He accepted all the arrangements made by Mahārāja Yudhiṣṭhira because He could not disobey the King, who was His elder cousin. The Lord plays the part of a subordinate in His transcendental sporting, and thus sometimes He puts Himself in the care of Yaśodāmātā for His protection in His so-called helplessness of childhood. That is the transcendental līlā, or pastime of the Lord. The basic principle for all transcendental exchanges between the Lord and His devotees is exhibited to enjoy a transcendental bliss for which there is no comparison, even up to the level of brahmānanda.