अनादिमध्यान्तमनन्तवीर्य मनन्तबाहुं शशिसूर्यनेत्रम्।पश्यामि त्वां दीप्तहुताशवक्त्रम् स्वतेजसा विश्वमिदं तपन्तम्॥
स्वतेजसा विश्वमिदं तपन्तम् || 19||
The verse says
I see you without beginning, middle or end, with endless power, with countless arms, the sun and moon your eyes, your mouth a blazing fire, burning this whole world with your own heat.
In plain words
The sun and the moon, as eyes.
The two things everybody in the world looks at, and in this vision they are the ones doing the looking.
And the last clause is the first mention of burning.
Where you've felt this · in health
You are walking home across open ground in the middle of a summer afternoon. There is no malice in it. The sun is not aiming at you and would be doing exactly the same thing if you had stayed indoors. You still find yourself moving faster toward the shade.
Going deeper
Heat without intent is a particular kind of frightening, and it is introduced here rather than later.
Nothing in this line describes anger. The burning is a property, like brightness, in the same list as the arms and the eyes. That is worse than hostility would be, because hostility can be addressed. You can appeal to something that means you harm. You cannot appeal to something that is simply hot.
Everything that happens between here and verse 32 is the working out of that single fact.
And it is the detail to hold when the chapter reaches its most famous line. What frightens Arjuna is not that he has met an enemy. It is that he has met something enormous that is not, in any sense he can use, paying attention to him specifically.