S. R. Faruqi:

There's the meaning of tab as 'fever, heat', and also the meaning of 'at that time'. That is, when the heart arrived in the body (that is, when we became aware of the heart), then the whole body burned and became ash (because there was so much heat in the heart); or when the heart arrived in the body, then because of the heat the whole body burned and became ash.

In the second line 'garment' is meaningful, because this is a metaphor for the body. The real body (that is, the body's most valuable thing) is the heart, and the body (that is, the outward body) is its clothing. Thus between the heart and the body there's the same relationship as between the body and a garment. The way that the burning of a garment doesn't necessarily imply the burning of the body, in the same way the burning of the body doesn't necessarily imply the burning of the heart. The heart itself is fire-- it keeps burning like the sun, but it doesn't turn to ash.

He has used this same theme in a comparatively weaker way in the second divan [{1045,5}]:

aatish sii phu;Nk rahii hai saare badan me;N mere
dil me;N ((ajab :tara;h kii chingaarii aa pa;Rii hai

[something like a fire is flaming up in my whole body
into the heart an extraordinary kind of spark has come and fallen]

Sauda too has composed well on this theme; a number of aspects of his verse resemble those of Mir's verse:

phuu;Nk dii hai ((ishq kii tab ne hamaare tan me;N aag
dahke hai juu;N shu((lah-e faanuus pairaahan me;N aag

[the heat of passion has blown into flame a fire in our body
fire has burned in the garment like flame in a candle-lantern]

[See also {847,9}; {1779,3}.]

FWP:

SETS == DOUBLE ACTIVATION
MOTIFS
NAMES
TERMS

ABOUT 'DOUBLE ACTIVATION': In this verse, we are required to read tab se in two entirely different senses 'since then' and 'from heat'; both are fully present and meaningful, and we cannot rule out either one. This kind of performance is rare and remarkable. It does not, however, guarantee that a verse is truly compelling. Here is one such uncompelling case [{102,7}]:

us ke lab se tal;x ham sunte rahe
apne ;haq me;N aab-e ;haivaa;N sam rahaa

[from her lips we kept hearing bitterness

with regard to us, it remained like the 'water of life'
with regard to us, poison remained the 'water of life']

For examples of Ghalibian 'double activation', see G{120,3}.

As SRF explains, the real focus of the verse is tab se in its two excellently appropriate senses. For another verse in this ghazal that turns on tab , see

{15,5}.

The body-as-garment metaphor is in fact forced upon our attention, since otherwise the second line would be quite anticlimactic (because having the body burn is so much more significant than merely having a garment burn).