Swami the above statement is like an excerpt from various chapters and compiled in one and for this Adiyen could find these references
Arjuna asked Krishna to lively witness his Vishvaroopam form, 11th chapter, 3rd slokam and Kannan’s answer in 8th slokam, by granting divine eyes. However, Krishna states the gunathith part ( True self) in 2nd chapter, 44th slokam, but not explicitly, and what hinders realising the true self is stated as a process in 2nd chapter, 62,63 slokams
.”Arjuna in Gita too asked a similar doubt to krishna, as why he isn’t able to see his true self just normally”
For this, 3.37, 38 slokam discuses the above statement of arjuna to krishna.