Bhagwad Gita
Chapter 12, Verse 5
क्लेशोऽधिकतरस्तेषामव्यक्तासक्तचेतसाम्।
अव्यक्ता हि गतिर्दुःखं देहवद्भिरवाप्यते।।12.5।।
For those whose minds are attached to the unmanifested, impersonal feature of the Supreme, advancement is very troublesome. To make progress in that discipline is always difficult for those who are embodied.