《论衡·卷二十七·定贤篇》
说话深得道理的核心，口才即使迟钝而不善辩说，而善辩已在心胸之中了。
言得道理之心，口虽讷不辩，辩在胸臆之内矣。
Speech which deeply comprehends the core of reason, is eloquence, even if it is slow and not good at argument, because good argumentation is already in the heart.