The Prophet Muhammad (peace be upon him) relays a sacred saying (Hadith Qudsi): "Neither My heavens nor My earth can contain Me, but the heart of My believing servant contains Me."

Sufis interpret this to mean that the heart is a treasury that holds the most precious secret: knowledge of Allah (Marifatullah). However, this treasury is locked. The key is Mujahada (spiritual struggle), Dhikr (remembrance of God), and the guidance of a perfected spiritual master (Murshid Kamil).

Before the book, there was the concept. In Islamic esotericism, particularly in the school of Muhyiddin ibn al-Arabi, the human heart (qalb) is considered the true Khazinat al-Asrar.

Khazinat al-Asrar set a precedent for the "didactic mathnawi." Its influence is evident in the works of later luminaries such as Rumi (specifically the Masnavi-i Ma'navi), Attar, and Jami.

Rumi, in particular, seems to have drawn heavily from Nizami’s structural approach—using anecdotes to break the flow of a main narrative to highlight a spiritual point. The concept that poetry can be a vessel for the highest metaphysical truths is a legacy cemented by this work.