Shaarei Teshuvah, Shaar 1, End of Paragraph 29:
Signs of humility include:
a soft answer, a low voice and lowered eyes.
These will remind him [a Jewish person]
to humble his [or her] heart.
Rabbi Simeon ben Zemah Duran (born 1361, died 1444) said in the introductory section of his book Magen Avot:
«None has arisen like him [Rabbeinu Yonah of Gerona]
to speak about fear of G-d, to draw the hearts of
the people to the paths of piety.»