Imam Khomeini has undertaken very useful discussions in this regard in his famous work of "an exposition on Forty Hadith" as following:
There are various applications and denotations of the word ‘heart’.
For physicians and the common people it is a tiny piece of flesh, whose contractions and expansions cause the flow of blood through arteries and veins, which generates a subtle élan vital.
The philosophers (hukama) use it for a certain seat of the psyche (nafs). The urafa assign to it grades (maratib) and stages (maqamat), and to go into their details is not our concern here.
In the Holy Quran and the ahadith, it has been used both in its general as well as its particular senses in different places.
In the verse:
The hearts reached to the throats. (33:10)
‘Heart’ is used in the same sense as used by physicians. And in
They have hearts wherewith they understand not, and they have eyes wherewith they see not. (7:179)
It is used in the sense used by the philosophers. And in:
Therein verily is a reminder for him who hath a heart, or giveth ear with full intelligence. (50:37)
‘Heart’ is used in the same sense as used by the urafa.
In the tradition, tafakkur is used in the sense as is generally used by hukama’, but the ‘heart’ as meant by urafa has no relation to tafakkur, especially on its certain levels, as those who are familiar with their terminology know well, Imam further explained.
In the statement:gives the sense of bu’d, to keep away, to shun, and such is its meaning in as given by al-Sihah. ‘Night’, here, has been used allegorically for ‘bed’ and as discussed in detail by the usuli faqih Aqa Shaykh Rida Isfahani in Jaliyyat al-hal, the avoiding of ‘night’ refers to getting up from the bed for night prayers God willing, we shall discuss the holy tradition in a number of sections.
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