The Prajñāpāramitā Diamond Sutra, or “The Sutra of the Perfection of Wisdom of the Diamond that Cuts Through Illusion” is a Mahayana Sutra that discusses the Signless Nature of the Buddha. The below picture reminds me of a reading from this sutra:-

“In a place where there is something that can be distinguished by signs, in that place there is deception. If you can see the signless nature of signs, then you can see the Tathagata.”