Why is the first jhana omitted from MN 125?

Why is the first *jhana* omitted from MN 125 ? How is this omission related to the context of that sutta? > As the placing of the mind and keeping it connected are stilled, they enter and remain in the second absorption … > *So vitakkavicārānaṁ vūpasamā ajjhattaṁ sampasādanaṁ cetaso ekodibhāvaṁ avitakkaṁ avicāraṁ samādhijaṁ pītisukhaṁ dutiyaṁ jhānaṁ …* > > third absorption … > *tatiyaṁ jhānaṁ …* > > fourth absorption. > *catutthaṁ jhānaṁ upasampajja viharati.* > MN 125