Bhagavad Gita Chapter 11.48
na veda-yajñādhyayanair na dānair
na ca kriyābhir na tapobhir ugraiḥ
evaḿ-rūpaḥ śakya ahaḿ nṛ-loke
draṣṭuḿ tvad anyena kuru-pravīra
O best of the Kuru warriors, no one before you has ever seen this universal form of Mine, for neither by studying the Vedas, nor by performing sacrifices, nor by charity, nor by pious activities, nor by severe penances can I be seen in this form in the material world.