The images we have had before us in the above verses are meant to introduce us to Virgin Mary (PBUH).
(… وَإِذْ قَالَتِ الْمَلَائِكَةُ ) (And [mention] when the angels said …): Garbiel (PBUH) is meant here.
( يَا مَرْيَمُ إِنَّ اللَّهَ اصْطَفَاكِ وَطَهَّرَكِ وَاصْطَفَاكِ عَلَىٰ نِسَاءِ الْعَالَمِينَ … ) (…“O Mary, indeed Allah has chosen you and purified you and chosen you above the women of the worlds): Here we have two types of being chosen. The first is: (indeed Allah has chosen you and purified you) where ‘above’ is not there; and the second is: (and chosen you above the women of the worlds.) where ‘above’ is there.
(… وَطَهَّرَكِ …) (…and purified you …): She is purified by heavenly orders because she will be accused since she gets pregnant while still a virgin: a miracle that is condemned by people of that era. Nonetheless, the Almighty wanted to give her the tidings of Jesus Christ (PBUH). Prior to that, the Almighty wanted to inform her that she had been chosen among the believers and above of the women in the worlds.