Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 25
Sanskrit:
क्वापि सन्ध्यामुपासीनं जपन्तं ब्रह्म वाग्यतम् ।एकत्र चासिचर्माभ्यां चरन्तमसिवर्त्मसु ॥ २५ ॥
ITRANS:
kvāpi sandhyām upāsīnaṁjapantaṁ brahma vāg-yatamekatra cāsi-carmābhyāṁcarantam asi-vartmasu
Translation:
Somewhere Lord Kṛṣṇa was observing the rituals for worship at sunset by refraining from speech and quietly chanting the Gāyatrī mantra, and elsewhere He was moving about with sword and shield in the areas set aside for sword practice.
Purport:
According to Śrīla Viśvanātha Cakravartī, the words sandhyām upāsīnam indicate sunset rituals, whereas the words asi-carmābhyāṁ carantam refer to sword practice, which takes place at dawn.