masii;h-e kushtah-e ulfat babar ((alii ;xaa;N hai
kih jo asad tapish-e nab.z-e aarzuu jaane
1) the Messiah of those slain by love is Babar Ali Khan
2) who, Asad, would know the heat of the pulse of longing
The meaning is clear: that Babar Ali Khan knows the pulse of the longing of his companions. Either 'Babar' or 'Babr' can be used; both are correct.
There's no telling what kind of a venerable elder Babar Ali Khan is. In any case, the one who can bestow life on those slain by love is a messiah, who is acquainted with the agitation of the pulse of longing.
For more on Ghalib's unpublished verses, see the discussion in {4,8x}. See also the overview index.
The 'Messiah' could be a specific reference to Hazrat Isa, or Jesus Christ, whose characteristic miracle in the Islamic tradition is to bring the dead back to life. Or it could be simply a reference to any 'messiah' in general, so that the same exclamatory and performative ambiguity is created as in {215,1}.
Ghalib corresponded with various people called 'Hakim', but Babar Ali Khan doesn't seem to have been among them. Perhaps the connection was only medical, for in 1865 he wrote to his friend and patron the Navab of Rampur, who had been ill. He began by saying that he himself was not a physician, but was 'a man of much experience'; he then poured out a stream of medical advice, including the following:
To strengthen the heart you should take the gold-and-ambergris electuary made up according to the prescription of the late Hakim Babar Ali Khan. Its ingredients are gold leaf, white ambergris, essence of kewra [a strong-scented flower], and white crystallized sugar--made to a special recipe in which the use of too many ingredients was deemed inappropriate. [Russell and Islam, pp. 321-322]
Hakims as practitioners of Unani medicine paid serious attention to their patients' pulse. But why is Babar Ali Khan singled out as a 'Messiah' who understands the hot pulse of those slain by love, and can perhaps even restore them to life? Was he known as such a brilliant hakim? Was he known for some kind of romantic involvement? It would be fun to know, but it's not really very important. Ghalib rarely uses in his verses the names of actual people from his own cultural world, so I've been careful to include such verses on the website.
Asi:
Oh Asad, Babar Ali Khan is the messiah of those slain by love-- one who well knows the heat of the pulse of longing.
== Asi, p. 288