What is the wisdom behind the difference in the waiting period ('iddah) for a woman whose husband has died, between a free woman and a slave woman, where for the former it is four months and ten days, and for the latter it is two months and five nights?

Slaves, in matters of waiting periods ('iddah), punishments (hudud), and divorce, are treated as subject to half of what free individuals are subject to. This is based on the Almighty’s saying regarding the punishment for a slave woman who commits adultery: {then for them is half of the punishment prescribed for free women}. Thus, the waiting period ('iddah) for a slave woman whose husband has died is two months and five days, which is half the 'iddah of a free woman. As for the wisdom behind this, Al-Qurtubi mentioned that a slave woman is weaker than a free woman, and her punishment is less because her blessings (نعمتها) are fewer.