What is the wisdom behind the the incident of the splitting of the Prophet's chest—peace and blessings be upon him—in his childhood, and why did this purification not occur spiritually without the splitting?

The splitting of the Prophet's chest (peace be upon him) occurred several times for different reasons:

1. In childhood: To extract the share of Satan from him, as mentioned in the Hadith of Anas ibn Malik in Sahih Muslim, ensuring his upbringing was infallible. 2. At the time of revelation: To further honor and purify him, preparing him to receive revelation with a strong and pure heart. 3. During the Mi'raj (Ascension): To prepare for converse with Allah, as stated in Bukhari, and it is possible that this was for the utmost bestowal and purification.

As for why the purification was not done without splitting, that is due to divine wisdom, and to show the Prophet's (peace be upon him) honor and Allah's care for him.