This process of becoming whole again can happen in one lifetime, or it can happen over many lifetimes. That is re-incarnation.
Each lifetime that we spend on this earth is part of eternity. Each lifetime brings us closer to being whole as individuals again, and that is why we return to this earth.
The bodies, people and circumstances we choose each time we return to the earth depend on what we need to learn here. Do we need to return as males or females? With other people from previous lives whom we have unfinished business with - or with different people?
Have you ever noticed that some people tend to have close bonds that are not affected by time of circumstances? Like lovers or twins that separate and meet again years later? Mother and daughter who are very close? Friends who live in different countries, but always remain in contact?
Could it be that such people have become whole to the extent that they are there to support one another on this part of the eternal journey?
The opposite is also true – that people experience intense destructive emotions about each other, but for some reason they cannot separate. We all know about the wife who in her mind has a very good reason for staying with a cheating or violent husband. The same holds for e.g. incestuous relationships and for abused and neglected children.
None of these happen by chance or by accident. It is all part of a Plan that spans centuries and lifetimes, and of a movement towards integrating first with our selves, and then with one another.
Eternity does not know time. We created time so that we can better understand the Plan.
Eternity also does not know form. We use bodies because we are not spiritually whole enough yet to leave those bodies behind.
We keep re-incarnating until we can, as in the example of the droplets, be re-integrated again.
Then, as with Nelson Mandela and Mahatma Ghandi and others like them, we return to this earth again, so that we can light the path for our brothers and sisters. Our aim is to re-integrate all souls, so that we can become One with God again.
That is what re-incarnation is about.
That is why we sometimes 'recognise' complete strangers and experience déjà vu (the strong, sure feeling that you have been in a particular place or situation before, even though your logical mind says it is impossible).
That is also why we sometimes have shocking daydreams about the people we love most, and why we often have such difficulty breaking away from the people that hurt us most.
Once we understand that we are part of eternity, it often becomes easier to understand the most joyful and most hurtful parts of our lives. Then we get closer to being like those perfect single drops of water that reflect the beauty of nature, or even to being like the collection of perfect drops that form a rainbow.