From Shlomo Carlebach loved every human

How can somebody who is not a Jew suddenly become a Jew? Two people
are learning together. Their letters become close to each other.
Their letters become married to each other. From this closeness, a
new soul is born. Somewhere at one end fo the world, two people were
learning. They drew so close to each other through their learning,
that as a result, the soul of someone standing at the opposite end of
the world is touched. The soul of this someone begins to shine.

Reb Nachman says this is also what happens to a Ba’al Tchuva.
Sometimes a person becomes completely engrossed in total darkness. In
some other part of the world, two people are learning together. The
coming together of their two letters draws down a light which breaks
the barrier of darkness surrounding this person engrossed in darkness.
It reawakens the soul of this person.