What is the main topic of Bulugh al-Maram Hadith 6?

Bulugh al-Maram Hadith 6 is from chapter "The Book of Purification". Summary: "Let him say in his heart..."

Bulugh al-Maram: Hadith 6

1. The Book of Purification

1/1 Chapter:

باب المياه

Bulugh al-Maram

وَأَخْرَجَهُ اِبْنُ حِبَّانَ بِلَفْظِ: { فَلْيَقُلْ فِي نَفْسِهِ } (102)‏ .‏

Ibn Hibban also reported the above Hadith with the version:

"Let him say in his heart..."

Reference: Bulugh al-Maram 86
In-book : Book 1, Hadith 104
English translation : Book 1, Hadith 92