Ibn Ezra, on Gen 1:5

“And he called the light Day, and the darkness Night; and there was evening and morning one day.”

““And He called” – The hey of layla is added, and it [i.e., the word] is accented on the penultimate syllable, and it is always masculine. “Evening” [erev - close in meaning to darkness, and it’s called thus since forms are mixed together [nitarvu i.e., indistinct]. “Morning” [boker] – the opposite of evening, for a person is able to check [l’vaker, i.e., to distinguish] between forms. The meaning of “one day” is referring to the rotation of the sphere. There is a secret to the midrash of six thousand. And after it has said that the light is called day, it isn’t possible that the evening should be called day, rather its explanation is “it was evening and also morning of Day One”, for if it was [referring to] the evening and morning(g of one day, what would be the meaning of “a second day”?”

Imported from an open dataset — not yet checked against the printed edition.