S. R. Faruqi:

This verse too is the bearer of an uncommon mood. Having assumed the heart to be a separate, affectionate, companionable person, to mourn for its going, and to search for the heart instead of for the beloved, is an entirely new theme. Because 'this road' has not been described, the eloquence [balāġhat] has increased. This can be the road of passion, it can also be the beloved's street, it can also be the road to the desert. Thus the sense of dil chhoṛ denā ['to leave the heart'] as 'to lose one's courage' is also possible: on the road to the desert, he would have lost his courage and his spirit would have failed him. 'I wander' is also very fine, because in it there's an image of purposeless roaming, and also a sense of not knowing what the next step should be.

This theme he has used twice in the second divan, but this mood hasn't been achieved. At the age of seventy or seventy-two, the poet has done what he couldn't manage to do in his youth. The verses from the second divan [{896,4}]:

ḳhāk yāñ chhānte hī kyūñ nah phiro dil ke liye
aisā pahuñche hai baham phir koʾī ġham-ḳhvār kahāñ

[why won't you wander around sifting through the dust for the heart?
hardly/where does such a sympathizer again come to us?!]

Also from the second divan [{933,6}]:

rahā thā ḳhūñ taʾīñ ham-rāh so āphī ḳhūn hai ḥaif
rafīq tujh sā milegā kahāñ dilā mujh ko

[I myself remained turned to blood; as a fellow-traveler, thus it itself is blood, alas
where will I find a companion like you, oh heart?]

Along with 'heart', the word aisā is very much in the idiom. About departed or left-behind people they say, ab aise log / dost / mihrbāñ kahāñ milenge . That is, people of the kind that the person was who is being discussed, or us jaise people. If he had said rafīq-e shafīq phir aisā , then the beauty of the idiom would not have been created.

FWP:

SETS
MOTIFS
NAMES
TERMS == IDIOM; MOOD; THEME

The verse also points up the lover's lostness and loneliness: apparently the only real friend he's ever had has been his own heart. And not only in the past, but for the future as well, his own heart is the only friend he can even imagine. Having lost such a unique and ideally loving companion, how can he ever be happy again?

The nice swingy rhyme of rafīq-e shafīq is an extra treat.

Of course, he sometimes takes quite an opposite view of the heart, as in {1343,1}:

jigar ḳhūñ kiyā chashm nam kar gayā
gayā dil so ham par sitam kar gayā

[having turned the liver to blood, having made the eyes wet, it went
when the heart went, it treated us cruelly and went]