Ashtavakra Gita
अंतर्विकल्पशून्यस्य बहिः स्वच्छन्दचारिणः। भ्रान्तस्येव दशास्तास्तास्- तादृशा एव जानते॥१४- ४॥
The state which is without desires within, and is carefree outwardly just like a mad man, can only be recognized by someone in the same enlightened state.
english translation
aMtarvikalpazUnyasya bahiH svacchandacAriNaH। bhrAntasyeva dazAstAstAs- tAdRzA eva jAnate॥14- 4॥
hk transliteration by Sanscript