Bhagavad Gita 15.3न रूपमस्येह तथोपलभ्यते नान्तो न चादिर्न च संप्रतिष्ठा।अश्वत्थमेनं सुविरूढमूल मसङ्गशस्त्रेण दृढेन छित्त्वा ॥

The idea is continued in the next verse.So long as one is under the sway of ignorance, he cannot understand the form of this tree, its end, origin and foundation (middle). O Arjuna Thou mayest perhaps consider that such a huge tree cannot be uprooted by any means whatever. It is not so. However firmly rooted it may be, it can be cut by the powerful axe of nnattachment or dispassion within the twinkling of an eye.After cutting this tree you will have to look within, meditate on the Self and behold the Supreme.Tatha As such As described above. Is it necessary to pull down castles in the air or to break the horns of a hare or to pluck a flower growing in the sky or to get butter from the milk of a tortoise or oil from stone Similarly, O Arjuna, there is no reality in this tree. Therefore why should you entertain any fear as to whether it may be uprooted or not Its form as such is not perceived by anybody here it is like a dream or a mirage or an imaginary city in the sky formed by the clouds or caused by a juggler. It appears and disappears. This tree has DrishtaNashtaSvarupa like the mirage. That object which is destroyed when one beholds it is DrishtaNashta. Nobody has perceived the end, the origin or the foundation of this illusory tree. No one can say that it has arisen from such and such a place or point.Samsara or the peepul tree is inveterately deeprooted