The quote "If it don't come back, it was never yours. If it comes back, it's yours to keep," from Marian Keyes' book "Angels," touches on the nature of possession and relationships. It suggests that the true value of something is reflected in its return. If something or someone departs from your life and doesn't return, it was never truly meant for you. This offers a sense of comfort, implying that you should not cling to what is not meant to stay.

Additionally, the idea reinforces the importance of acceptance and letting go. When something returns, it signifies its genuine connection to you, highlighting the notion that the bonds we cherish often come back to us. Keyes’ words encourage embracing loss as a natural part of life, while simultaneously fostering hope that what is meant for us will eventually find its way back.