CC Madhya 8.40
nānyathā kalpate kvacit
“ ‘My dear Lord, sometimes great saintly persons go to the homes of householders, although these householders are generally low-minded. When a saintly person visits their homes, one can understand that it is for no other purpose than to benefit the householders.’
This verse is from Śrīmad-Bhāgavatam (10.8.4).