What is the significance of the Muslim saying "Inna lillahi wa inna ilayhi raji'un" when someone passes away?

The Muslim saying "Inna lillahi wa inna ilayhi raji'un" translates to "Verily, to Allah we belong and to Him we shall return." It is recited when someone passes away to remind believers of the temporary nature of life on Earth and the belief in the afterlife. It serves as a way to express acceptance of Allah's will and to seek comfort in the face of loss.