Weekly Hadith: “The religion is sincerity”

This is Hadith #7 in Imam Nawawi’s collection. What did the Messenger of Allah (ﷺ) mean by “Naseehah” (Sincerity)?

Full Lesson by our brother Abu Arwa Ali:

Alhudabolton.com/2019/01/20/40-hadith-lesson-16/