S. R. Faruqi:

For its 'mood' and the freshness of its image (within the breast, someone keeps scouring the heart), this verse is uncommon. In the first line, the ambiguity too is fine. (1) We don't know what the manner/mode of passion is. That is, we don't know how passion treats its own people. (2) We don't know the method of passion-- that is, we don't know how to be a lover. The theme of this verse (especially the image in the second line) seems to be Mir's own invention. A number of poets have imitated it.

Mir himself has composed it several times. From the second divan [{1030,1}]:

kis ġham meñ mujh ko yā rab yih mubtalā kiyā hai
dil sārī rāt jaise koʾī malā kiyā hai

[in what grief, oh Lord, has it involved me--
the heart, all night, as if someone always scoured it?]

From the fifth divan [{1743,4}]:

ʿishq-o-muḥabbat kyā jānūñ maiñ lekin itnā jānūñ hūñ
andar hī sīne meñ mere dil ko koʾī khātā hai

[what do I know of passion and love-- but I know this much
only/emphatically within my breast, someone eats the heart]

On this theme, a verse by Sheftah is on the lips of great and small:

shāyad isī kā nām muḥabbat hai sheftah
ik āg sī hai sīne ke andar lagī huʾī

[perhaps love is the name of this, Sheftah
something like a singular fire has taken hold within the breast]

The theme of a fire within the breast, others have composed as well. For a few examples, see

{847,1}.

Fani has well used the image of a thorn:

maʿlūm nahīñ kyā hai muḥabbat lekin
kāñṭā dil meñ khaṭak rahā hai koʾī

[I do not know what love is, but
some thorn is pricking in the heart]

Undoubtedly Fani's verse is very beautiful, but after Mir, the theme of a scouring of the heart has been used only by Jur'at. It seems that Jur'at wrote a 'reply' to Mir. And the truth is that he wrote a very good one:

pūchho nah hijr kī shab jurʾat se mere ṣāḥib
dil sārī rāt jaise koʾī malā kiyā hai

[don't ask Jur'at about the night of separation, my dear sir
for the whole night, it's as if someone always scoured the heart]

FWP:

SETS
MOTIFS
NAMES
TERMS == FAUX-NAIF; MOOD; REPLY; THEME

SRF has given us an elegant exposition of one side of malnā , but let's not forget the other side (see the definition above)-- the side that gives us 'to rub, to rub down, to furbish, to anoint'. For after all, isn't that part of the mesmerizing quality of passion, that it alternately (or even simultaneously) inflicts torment and delight?