The incarnation was not initially imposed on the spirits as a punishment. It is rather necessary for the spirits' improvement and for the fulfillment of God's works. Everyone has to submit to it, no matter if one takes the evil or the good path. Only those who take the good path will improve quickly, they do not delay to arrive at the end in less painful conditions.
Allan KardecIn order to cooperate in the material worlds as agents of a divine power, the spirits temporarily have a material body. By the work required in their corporeal lives, the spirits improve their intelligence and, by observing God's law, they acquire the merits which will lead them to eternal happiness.
Allan KardecIn a word, what characterizes the spiritist revelation is that while divine in its origin and of the initiative of the Spirits, its elaboration is fruit of manโs work.
Allan Kardec