देवैरत्रापि विचिकित्सितं पुरा न हि सुविज्ञेयमणुरेष धर्मः ।अन्यं वरं नचिकेतो वृणीष्व मा मोपरोत्सीरति मा सृजैनम् ॥ २१ ॥
In plain words
Even the gods of old had doubt about this; this reality is subtle, not easily known. Choose another boon, Naciketas -- do not press me on this, release me from it.