Mukherjee(2012) said: "A principal sloka (verse) in the Bhagavad Gita announces the repeated return of Vishnu for the destruction of evil." (Souvil Mukherjee, "Vishnu and the Videogame: The Videogame Avatar and Hindu Philosophy", 2012. (presented at the Philosophy of Computer Games Conference, 2012)). But Souvil didn't notice the numbers of verses in BhG.
I guess the verses are thus (with my 大雑把訳 in Japanese language):
photograph of the BhG text of Poona Critical Edition is [this].
ajo'pi sannavyayaatmaa bhuutaanaamii^svaro'pi san/(吾は不生 本性不変の 万物主 我が原質により 我は幻出)
prak.rti.m svaamadhi.s.thaaya sa.mbhavaamyaatmamaayayaa//4-6 yadaa yadaa hi dharmasya glaanirbhavati bhaarata/(アルジュナよ ダルマの衰退 あるたびに 非法流行れば 我は現わる)
abhyutthaanamadharmasya tadaatmaana.m s.rjaamyaham//4-7 paritraa.naaya saadhuunaa.m vinaa^saaya ca du.sk.rtaam/(ユガごとに 善人たすけ 悪くじき ダルマのために 我は現わる)
dharmasa.msthaapanaarthaaya sa.mbhavaami yuge yuge//4-8