病は口より入り禍は口より出ず

やまいはくちよりいりわざわいはくちよりいずyamaihakuchiyoriiriwazawaihakuchiyoriizu

expression · Nidan verb (lower class) with 'dzu' ending (archaic)

1. be moderate with your mouth
2. sickness enters through the mouth, calamities come out of the mouth

Study it in Yanamino