divi sūrya-sahasrasya
bhaved yugapad utthitā
yadi bhāḥ sadṛśī sā syād
bhāsas tasya mahātmanaḥ
diviin the sky; sūrya—sun; sahasrasyaof many thousands; bhavetthere were; yugapatsimultaneously; utthitāpresent; yadiif; bhāḥlight; sadṛśīlike that; —that; syātmay be; bhāsaḥeffulgence; tasyathere is; mahātmanaḥof the great Lord.
If hundreds of thousands of suns rose up at once into the sky, they might resemble the effulgence of the Supreme Person in that universal form.
What Arjuna saw was indescribable, yet Sañjaya is trying to give a mental picture of that great revelation to Dhṛtarāṣṭra. Neither Sañjaya nor Dhṛtarāṣṭra were present, but Sañjaya, by the grace of Vyāsa, could see whatever happened. Thus he now compares the situation, as far as it can be understood, to an imaginable phenomenon (i.e. thousands of suns).

Link to this page: https://prabhupadabooks.com/bg/11/12

If you Love Me Distribute My Books -- Srila Prabhupada