There was a proverb that said, "He who works virtue does so in solitude, but he who works folly seeks companions." Grief awaited anyone who followed after such people.
善行をする者は ひとりで やりたがり、愚行をおこなう者は仲間をほしがる -- そういう警句がある。道づれにされる者はたまらない。
Original text (Japanese)
Notes from Wikiquote
Compare with wiktionary:misery loves company.