Spirits cannot aspire to perfect happiness as long as they are impure. Any kind of blemish prevents their entry onto blissful worlds. They are like the passengers on a plague ship, to whom entrance to a town is forbidden until they have been purified. It is in their many corporeal existences  that spirits rid themselves little by little of their imperfections. The trials of life enable advancement when well accepted. As expiations, they erase wrongs and purify. It is the medicine that cleanses the sores and heals the patient. The graver the illness, the stronger the medicine must be. Therefore, those who suffer greatly must tell themselves  that  they have much to expiate, and should rejoice at being healed sooner. It depends on them, through resignation, to make such suffering profitable and not to waste the fruit by complaining. Without resignation, they will have to start all over again.