SB 10.69.36
avyakta-lingam prakrtisv
antah-pura-grhadisu
kvacic carantam yogesam
tat-tad-bhava-bubhutsaya
Translation:
Somewhere Krsna, the Lord of mystic power, was moving about in disguise among the homes of ministers and other citizens in order to understand what each of them was thinking.
Purport:
Although Lord Krsna is all-knowing, while executing His pastimes as a typical monarch He sometimes traveled about incognito to acquire necessary information about His kingdom.