Imam Ibn al-Qayyim
رحمه ﷲ said:
الدين كله خلق فمن زاد عليك في الخلق: زاد عليك في الدين
“The entire religion (al Islam) is good character, so the one who exceeds you in good character, has exceeded you in religion.”
See Madārij as-Sālikīn (Vol. 2 pg. 307)