FWP:
SETS == DEFINITION
One way to create an enchantment is to recite the magically efficacious words, and to 'blow' them (see the definition above) with the same breath, even as they are recited, into the ear of the enchantee; or else over some medium, like a bowl of water, that would then receive and transmit the enchantment when someone consumed it. The life-restoring effect of the breath of Jesus, when he blows on someone, is only superficially similar, since he uses Divine power rather than magic.
Magic itself is, strictly speaking, forbidden to good Muslims, but there's a very wide folkloric and narrative grey area in which figures like Hazrat Khizr move with dexterity and ease. The whole dastan tradition, including the vast Hamzah cycle, is overwhelmingly full of all sorts of magic, both the illicit kinds created by evil magicians, and the acceptable 'white' kinds that are taken to be sponsored in some vague or indirect manner by divine powers or representatives.
So this verse appears as a kind of neutral question, not implying on the face of it any special accusation of evil. As Bekhud Mohani notes, the address to the Lord may imply that he is considered ultimately responsible; or, of course, it may just be the usual exclamation, 'oh lord!' or 'oh God!'. The inshaa))iyah structure of the verse leaves the interpretive possibilities as open as possible.
Another question raised by the verse might be called a definitional one. The verse asks about the source of the 'incantation of waiting' that 'they'-- unspecified, and therefore presumably to be taken as 'people in general'-- would call 'longing'. This might be just a clever way of providing a (quasi-)definition of 'longing': what people take to be a human emotion is really the result of a magic spell.
But the verse also leaves open the possibility that the people
who identify this 'incantation of waiting' as 'longing' are wrong. It might
not really be the nature of longing that's at issue, but rather the erroneous
judgments made by the 'people in general' who view such emotions from the outside. 'They' think that there exists a spontaneous human emotion called
'longing' that is generated by lovers from their own hearts. But in fact what
they are seeing is the operation of an irresistible magic spell, such that
the poor lovers are really victims of enchantment, frozen into attitudes of
perpetual 'waiting', like Sleeping Beauty in the English fairy-tale tradition.
Nazm:
The amazement is over this: the moment love appears, how has longing been produced, and how did the incantation of waiting take effect? By the interrogative is meant not a real inquiry, but rather an expression of surprise or wonder. (258)
== Nazm page 258