Or what is the use of all this extensive knowledge, oh Arjuna? I support this entire universe with a single portion of Myself.

The concluding verse of the chapter. Bahunā etena — with all this extensive — kim — what? — jñātena — with knowing it. The point is not to memorize the list, but to understand the principle.

Viṣṭabhyāham — supporting, pervading — idaṃ kṛtsnam jagat — this entire universe. Ekāṃśena — with a single portion — a partial expansion of the Lord.

This anticipates the next chapter: the Viśvarūpa Darśana, where Arjuna will see the entire universe as a portion of the Lord.