Rabbi Chananiah ben Teradion said: If two sit together and no words of Torah are interchanged between them, theirs is the session of the scornful, as it is written (Psalm 1:1) “Nor sit in the seat of scoffers.” But when two sit together and words of Torah pass between them, the Divine Presence rests between them, as it is written (Malachi 3:16) “Then those who revered the LORD spoke with one another. The LORD took note and listened, and a book of remembrance was written before him of those who revered the Lord and thought on his name.” (m.Avot 3:3)