A Christian must be courteous to all. His words and deeds should breath with the grace of the Holy Spirit, which abides in his soul, so that in this way he might glorify the name of God. He who regulates all of his speech also regulates all of his actions. He who keeps watch over the words he is about say also keeps watch over the deeds he intends to do, and he never goes out of the bounds good and benevolent conduct. The graceful speech of a Christian is characterized by delicateness and politeness. This fact, born of love, produces peace and joy. On the other hand, boorishness gives birth to hatred, enmity, affliction, competitiveness, disorder and wars.
St. Nektarios of Aegina