rasulullah (saw) mentioned in a hadith that those souls who knew each other in the realm of souls [alim e arwah] would find and know each other in this world too, and those who developed animosity in that realm would dislike each other here as well. 

and that’s why, when you meet certain people, you’re suddenly overcome with a feeling that you know them from somewhere or that you’ve met them before. and maybe this also accounts for those moments when your heart misses someone you’ve never met, because your soul is yearning for those other souls and waiting for them to show up in your life here in this world.

isn’t that beautiful, subhan Allah?