One face for both: the same toward enemy and friend, the same in honor and disgrace, in cold and heat, in pleasure and pain.

Honest limit: the extant comment is a bare restatement.

What survives from Shankara here is only a restatement of the verse itself, the same toward foe and friend, in honor and dishonor, in cold and heat, in pleasure and pain, free of attachment everywhere, closed with a forward-pointing note, further marks, gesturing at what is still to come in the chapter. No fuller argument on this particular verse is preserved. It would be tempting to reach for his familiar architecture elsewhere, that such evenness marks a mind already purified by prior discipline, but that fuller claim is an inference from his broader system, not something this verse's record actually gives in his own words.

Read as evenness deepened under the friend and foe's real presence.

Ramanuja treats this verse as building on what he has already said: earlier, freedom from hatred toward foe and friend was named in the abstract. Now he adds that this same evenness must hold even when the foe and the friend are actually, concretely present, tested by their real nearness rather than by the mere idea of them. He traces this to a mind already settled in the self and unattached to dwellings, and he closes the whole catalogue as he began it, naming this even-minded, devoted person as dear to Me, devotion's discipline surpassing mere self-settledness.

Honest limit: no comment survives.

The record here is direct rather than merely thin: Madhva does not comment on this verse. Nothing should be invented in his name. If one wanted to extend his settled doctrine of total dependence on Hari to this verse, clearly labeled as extrapolation and not his word, one might expect him to read this evenness as a further mark of rightly ordered dependence, a competence sustained by the Lord rather than a self-generated achievement. But that is a guess built from his system elsewhere, not a citation from here.

Genuine, but drawn from his combined reading of 12.15-12.20, not this verse alone.

Abhinavagupta does not comment on 12.18 by itself; he reads verses 12.15 through 12.20 as one continuous passage and gives his remarks in full at 12.15. There he describes a mind that never locks onto the thought this one thing is mine to do, taking pleasure, pain, and everything else exactly as it comes, resting fully in the Lord who is the whole field of being, and reaching, with ease, the highest oneness. This bears directly on the pairs named in 12.18, but it belongs honestly to the combined passage rather than to this verse's specific wording.

Read as non-attachment generating the evenness, not the reverse.

Sridhara reads samah as one face for both, applied identically across all four pairs, and he calls the devotee empty of high spirits and empty of gloom, stressing that no residue is left over from either praise or insult once each has passed. He places freedom from attachment last in the verse because, on his reading, it is the root the other equalities grow out of: a person who clings nowhere has nothing left for enmity, disgrace, cold, or pain to seize upon.

A caution against over-reading a thin source.

The one paragraph surviving from Madhusudana here stays close to the plain sense: the four pairs are named, and the outcome, dear, is stated, without further technical elaboration on this particular verse. A responsible modern reading resists inflating this compact note into a larger staged theory of equanimity the source itself does not develop here, and instead lets the thinness of the record stand as it is.