S. R. Faruqi:

This is a verse only of 'mood', there's no excellence of meaning in it. But instead of saying 'from the beloved' or 'from the beloved's house', to say only 'from that direction'; and instead of saying 'written by the beloved', to say 'written by those hands', has two excellences of 'implication'. One is that in this way the verse becomes entirely spoken to himself.

The second is that the state of absorption and concentration becomes manifest, since he says 'from that direction' and 'by those hands' and considers that everyone will understand that he means the beloved. Or again, perhaps he doesn't even care whether the hearers will be able to understand the meaning of 'from that direction' and 'by those hands'. In both cases, his absorption is established.

Then there's his lover-like innocence, since he suspects that the throbbing of his heart has had an effect over there as well. Most people will call it a 'psychological' [nafsiyaatii] verse-- although to call such verses 'psychological' is to insult them. This verse has been made possible through traversing way-stations of the discernment of human life and human passion, to which psychology has no access. If poetic creativity is applied to the daily affairs of life, only then such a verse can come into being.

FWP:

SETS
MOTIFS == WRITING
NAMES == MESSENGER
TERMS == IMPLICATION; MOOD

SRF speaks of 'lover-like innocence' in that the narrator apparently believes that his throbbing heart has somehow managed to influence the beloved. To my mind a much more plausible explanation for his confidence is that he is relying on an omen. There are so many forms of divination, in South Asia as in other cultures, that are based on the observation of small chance events. For example, 'for the eye to pulsate' [aa;Nkh pha;Raknaa] is 'To feel a pulsation in the eye (if the pulsation be in the right eye of a man or the left of a woman it is regarded as an omen of some desirable event, whilst the contrary is considered unlucky)' (Platts p.95). To take an omen from an unusual throbbing or pounding of the heart seems a natural extension of this kind of prediction.

But even if we want to deny any traditional predictive power to this particular kind of omen (a wildly throbbing heart), the speaker still looks like a mad lover, ignoring all signs and tokens in the outside world, drawing arbitrarily-defined omens only from his own heart palpitations. Even then, most poignantly, he doesn't quite dare to anticipate that she herself will come. Rather, 'someone' will come from her general vicinity-- 'from that direction'. Or perhaps the 'someone' will be the Messenger, bearing an actual letter written by 'those hands'! And isn't this typical tabloid-horoscope language? 'Someone will send you a message; aid will soon appear unexpectedly'.

Compare Ghalib's take on the process of divination:

G{174,6}.