S. R. Faruqi:

This verse is, so to speak, a 'commentary' on the previous one [selected for SSA, {1052,7}]-- that is, an expression of opinion. If this verse from the second divan itself is kept in mind, then the idea can become even clearer. From the second divan [{980,11}]:

dil aur ʿarsh donoñ pah goyā hai un kī sair
karte haiñ bāteñ mīr-jī kis kis maqām se

[over both the heart and the highest heavens is, so to speak, his range
from what-all halting-places Mir-ji speaks!]

That is, to the speaker/Mir no theme is closed off. He can converse from every 'halting-place' (or converse about every 'halting-place')-- ground, sky, body, spirit, hunger, fullness, hatred, love. Thus the one who understands him too ought to have a gaze as deep, and a spiritual/inward journey as encompassing.

Muhammad Hasan Askari has taken 'halting-place' to mean the Sufistic maqām , and has said that here the suggestion is that we keep passing through different 'stages' of mystical knowledge and speaking about them. Thus only he can understand us who is aware of those 'stages'. There's no problem with this interpretation. But it will not be proper to limit the verse to only this. The verse [{980,11}] that I cited makes it perfectly clear that maqām can mean not only an inner 'mood', but also geographical places, different stages of a journey, and so on.

In the same way, there's also no harm in taking maqām to mean a musical tone. Especially since Mir also had a special awareness/feeling of the harmony and melody of his verses. The next point is that in Persian, for understanding or coming to understand an idea bah suḳhan rasīdan is used, and in Urdu bāt tak pahuñchnā . In this regard there's a zila between suḳhan and maqām .

If the insha'iyah interrogative in the first line is taken as a rhetorical question, then an interesting meaning emerges: 'How simple it is to understand Mir! He says every idea with regard to a single 'halting-place' (a Sufistic 'stage', a musical tone, etc.)'. If that 'halting-place' would become known, or it would become known that in Mir's poetry there's a single a central 'halting-place', then it would become very simple to understand it. It's an interesting verse.

FWP:

SETS == EK; KYA; POETRY
MOTIFS
NAMES
TERMS

In the first line the 'kya effect' of course operates most delightfully. It either isn't (1a), or is (1b), remarkably simple to understand Mir's poetry-- or perhaps the speaker is puzzled and is inquiring (1c).

Every poem or utterance of Mir's comes from ik 'halting-place'. This doesn't at all have to mean that each one comes from the same halting-place (that would require vuhī ). Rather, each one comes from a 'single' halting-place-- or, of course, a 'particular', or a 'unique', or an 'excellent' one; as usual, we are left to choose the reading for ourselves. And the possible range of such 'halting-places' is exceedingly wide (see the definition above), since it includes the geographical (when travelers pause in their journey to camp somewhere), the Sufistic of course (since the spiritual journey too has its 'stages'), and the situational ('situation', 'occasion', 'state'); it even culminates, as SRF has noted, in the musical.

It's also intriguing to contemplate whether coming from such a 'halting-place' would be likely to make a poem or an utterance simple to understand, since the 'halting-place' might act as a (metaphorical?) form of rest or recognizability for the reader. Or might it make things the very reverse of simple? After all, every single utterance might have a radically different perspective from that of every other one-- and Mir claims for himself in {980,11} such a cosmic range of possible 'halting-places'.