Arjuna is asking Krsna to explain His all-pervading nature so that in the future people will understand, especially the impersonalists. One should know that this is being asked by Arjuna on behalf of the common people. BG 1972 purports

Expressions researched:
"One should know that this is being asked by Arjuna on behalf of the common people"

Bhagavad-gita As it is

BG Chapters 7 - 12

For him there is no doubt, Yet he is asking Kṛṣṇa to explain His all-pervading nature so that in the future people will understand, especially the impersonalists, how He exists in His all-pervading aspect through His different energies. One should know that this is being asked by Arjuna on behalf of the common people.

BG 10.16 (1972), Translation and Purport

Please tell me in detail of Your divine powers by which You pervade all these worlds and abide in them.

In this verse it appears that Arjuna is already satisfied with his understanding of the Supreme Lord Kṛṣṇa. By Kṛṣṇa's grace, Arjuna has personal experience, intelligence and knowledge and whatever else a person may have through all these agencies, and he has understood Kṛṣṇa as the Supreme Personality of Godhead. For him there is no doubt, Yet he is asking Kṛṣṇa to explain His all-pervading nature so that in the future people will understand, especially the impersonalists, how He exists in His all-pervading aspect through His different energies. One should know that this is being asked by Arjuna on behalf of the common people.