Bhagavad Gita 7.24

अव्यक्तं व्यक्तिमापन्नं मन्यन्ते मामबुद्धय: |
परं भावमजानन्तो ममाव्ययमनुत्तमम्

Translation

The less intelligent think that I, the Supreme Lord Shree Krishna, was formless earlier and have now assumed this personality. They do not understand the imperishable exalted nature of My personal form.