“Silence should be kept secretly and in
your heart. Make sure that is not obvious to others that you maintain
silence. As soon as you have said two or three words, continue
immediately inside of you to send prayers for everybody to the Lord.
Embrace secretly in your heart, with love, the entire world. All the
Church … Make holy your silence by praying so is not sterile and
barren.”
(Saint Porphyrius Kafsokalyvitis, Anthology of Advices, p. 281)
http://www.orthodoxpath.org/spiritual-life/silence-should-be-kept-secretly-and-in-your-heart/
