"Brethren, it is easier to declaim against a thousand sins of others, than to mortify one sin in ourselves"

In this quote, John Flavel is reminding his audience that it is much easier to slam and mention the defects and errors of aside from to actively work on resolving our own. He is stressing the value of self-reflection and self-improvement, instead of simply criticizing and judging others. The word "mortify" in this quote describes the act of subduing or conquering something, in this case, an individual sin or flaw. Flavel is recommending that we should concentrate on attending to and working on our own imperfections rather of focusing on those of others. This quote serves as a suggestion that true growth and improvement starts with oneself.