Bhagavad Gita, Chapter 10, Verse 16

You should indeed speak, without reserve, of Your divine attributes by which, filling all these worlds, You exist.

Arjun asks for something concrete here, real, specific ways to actually recognize this presence, not abstract reassurance.

Wanting to meditate accurately, Arjun requests real detail rather than settling for a vague sense of closeness. The question itself shows how seriously he's taking the practice.