Bhagavad Gita · 11.50

सञ्जय उवाचइत्यर्जुनं वासुदेवस्तथोक्त्वास्वकं रूपं दर्शयामास भूयः।आश्वासयामास च भीतमेनंभूत्वा पुनः सौम्यवपुर्महात्मा॥

sañjaya uvācha ity arjunaṁ vāsudevas tathokvā svakaṁ rūpaṁ darśhayām āsa bhūyaḥ āśhvāsayām āsa cha bhītam enaṁ bhūtvā punaḥ saumya-vapur mahātmā

Sanjaya said: Having spoken thus to Arjuna, Krishna once again displayed his own gentle form. The great soul consoled the frightened Arjuna by assuming his pleasant appearance.

— Bhagavad Gita 11.50

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)