It was the desire of the Mother to simply create, in material form, a planet of such beauty and diversity and with so many kingdoms that it would literally be a petri dish for love.
Archangel Michael explains this in a personal reading shared by Steve Beckow, channeled through Linda Dillon
Archangel Gi’Anna ~ Embodying planet Earth as a petri dish for love
Steve Beckow: If there are only 144 archangels and trillions of planets and stars, not all of them embody archangels, do they?
Archangel Michael: No, they do not. There are planetary systems that have been created from sheer energy. There are planetary systems that have been created, as what you would think of, from elements. There are a whole variety of differences in them, not only the planetary systems.
But also remember that the number that archangels are able to assume… think of it as aspects… is massive.
SB: But are you saying that a planet doesn’t have to have an archangel?
AAM: No, absolutely not.
SB: Well, even the notion that an archangel does embody it is new to us, but now…
AAM: The embodiment, the form that Gi’Anna [i.e., anna or angel Gaia] has assumed is highly unusual.
SB: In what way, Lord?
AAM: That an archangel would be so committed to one aspect of the Mother’s Plan that she actually assumed this form in order for a long, long term service to the Mother.
SB: This is unusual?
AAM: It is highly unusual.
SB: Is there another planet that you can name where this has also happened?
AAM: No.
SB: What made Earth so special that it should be hosted by an archangel?
AAM: It was the desire of the Mother to simply create, in material form, a planet of such beauty and diversity and with so many kingdoms that it would literally be a petri dish for love.
SB: That helps me understand why the rest of the universe would be watching our progress and also why this planet would receive such help in ascension.
AAM: That is correct.