What is the main topic of Bulugh al-Maram Hadith 152?

Bulugh al-Maram Hadith 152 is from chapter "The Book of Purification". Summary: and Ibn Al-Madini said, "It is better than the Hadith of Busra".

Bulugh al-Maram: Hadith 152

1. The Book of Purification

1/10 Chapter:

باب الحيض

152

Bulugh al-Maram

وَقَالَ اِبْنُ اَلْمَدِينِيِّ: هُوَ أَحْسَنُ مِنْ حَدِيثِ بُسْرَةَ.‏

and Ibn Al-Madini said, "It is better than the Hadith of Busra".

Reference: Bulugh al-Maram 72
In-book : Book 1, Hadith 86
English translation : Book 1, Hadith 78