Thanks for the question! It’s been a while since I did this translation, and, like you, I am no Sanskrit scholar. So let’s see if my translation holds up.
Here’s the verse in the Catusparisat:
na hi santaḥ prakāśante viditvā lokaparyayaṃ |
śāntā hi nityato buddhās tīṛnā lokaviṣaktikāṃ
The verse is part of the exchange between the newly-awakened Buddha and the ajivaka ascetic Upaka (Upaga in Sanskrit). It is therefore parallel to Pali passage in MN 26:
https://suttacentral.net/mn26/en/sujato#25.23
However the Pali has no verse that parallels the Sanskrit here. There are at least two parallels to this verse in Sanskrit, all of them in the same context. One is in the Udanavarga:
na hi santaḥ prakāśyante viditvā lokaparyāyam ।
ādeśayanto virajaḥ padaṁ śāntamanīṣiṇaḥ
And one in the Sanghabhedavastu (where the Buddha’s biography is given as part of the Mulasarvastivada Vinaya):
na hi santaḥ prakāśante viditvā lokaparyāyam |
ājñānirvṛtabuddhās te tīrṇā lokaviṣaktikām
As you can see, the relevant pada is virtually identical in all three versions, while the second pada is quite different. So that’s not much help! But at least it reassures us that the reading is genuine.
The context is that the Buddha is completing his exchange with Upaka, and just said that he will travel to Benares to beat the drum of the Deathless.
In my translation, I omitted the particle hi, which is sometimes mere filler in verse. But on reflection I think it should be included, as I think these lines link back to that verse.
In addition, I think the overall point of the lines is to say that, since the Buddhas understand the way of the world, they point out a different path. I don’t think it is pointing to a doctrine of nothingness, as that would be an abrupt and unnecessary philosophical tangent. Generally, it is best to understand things in the simplest way possible (“The Principle of Least Meaning”).
Even though there is no exact parallel, the Pali texts do have a similar phrase in Dhp 304:
Dūre santo pakāsenti,
himavantova pabbato;
Translated by Buddharakkhita:
The good shine from afar, like the Himalaya mountains. But the wicked are unseen, like arrows shot in the night.
Here the highly ambiguous santo is read as “the good”, which is probably right. But the sense of the verse is still obscure to me. Perhaps it is giving the opposite message to the Dhammapada verse above: Upaka is unable to recognize the Buddha, so the verse is saying that the good are not obvious to see on the surface.
I would probably translate the two verses something like:
I will go to Benares
Sounding the Drum of the Deathless
To roll forth the Wheel of Dharma
That cannot be rolled back in the world.
For the good are not always apparent,
having understood the way of the world.
Always peaceful, the Buddhas
have crossed over clinging to the world.
But I admit I am still uncertain!
