Abba Iperechios gives the following counsel to those who are abstinent and practice fasting: “Eat meat and drink wine and do not devour your brother’s flesh with slander.”
And further: “By slandering God, the serpent was able to cast the first-created out of Paradise. He who slanders his neighbor does the same thing; he burdens his own soul and leads the one who listens to him to evil.”
Jesus says “Don’t judge others because you open yourself to judgment.” Same could be said of slander. But both concepts share the same basic principle. Both are examples of a failure to mind one’s own business. If one is going to abstinent and fast and yet say nasty things about a neighbor, then one might as well give up abstinence and fasting because those practices will be outweighed by the slander one speaks.
Abba Iperechios’ example is that of the serpent in the Garden, telling lies about God and we all know what that lead to. Would any of us want to be responsible for a neighbor’s perdition?