This is one of the most celebrated shlokas in the entire Gita. 'Mamaivamshah' — my own fragment. Krishna declares: every living being in this world is an eternal part of me. Like a thousand lamps lit from a single flame, each carrying that same light, every soul carries a spark of the divine.
This fragment is eternal — it was never absent, and it will never cease to be. Only the bodies come and go. This living soul draws toward itself the five senses (hearing, sight, touch, taste, smell) along with the mind as the sixth, and through them engages with the material world.
Grandmothers often tell their grandchildren: you are a part of God. This shloka is the scriptural root of that teaching. The same supreme being described in 15.6 as dwelling in the 'param dhama' is present as a fragment within every creature.