CC Madhya 22.54

‘sādhu-saṅga’, ‘sādhu-saṅga’ — sarva-śāstre kaya
lava-mātra sādhu-saṅge sarva-siddhi haya
Synonyms: 
sādhu-saṅga sādhu-saṅga — association with pure devotees; sarva-śāstre — all the revealed scriptures; kaya — say; lava-mātra — even for a moment; sādhu-saṅge — by association with a devotee; sarva-siddhi — all success; haya — there is.
Translation: 
“The verdict of all revealed scriptures is that by even a moment’s association with a pure devotee, one can attain all success.
Purport: 

According to astronomical calculations, a lava is one eleventh of a second.