157 Avot 3/2-4

(2) Rabbi Chanina, the Deputy High Priest, says: Pray for the welfare of the government, for were it not for the fear of it, man would swallow his fellow alive. Rabbi Chananya ben Teradyon says: Two who are sitting together and there are no words of Torah [spoken] between them, this is a session of scorners, as it is said (Psalms 1:1): “[Happy is the man who has]... not sat in the session of the scorners.” But two who are sitting together and there are words of Torah [spoken] between them, the Divine Presence rests with them, as it is said (Malachi 3:16): “Then those who feared the Lord spoke one with another, and the Lord hearkened and heard, and a book of remembrance was written before Him, for those who feared the Lord and for those who thought upon His Name.” I have no [Scriptural support for this] except [in a case of] two. From where [is there proof that] that even [when there is only] one [person studying Torah], the Holy One, blessed be He, determines a reward for him? As it is said (Lamentations 3:28): “He sits alone and is silent, since he takes [a reward] for it.”

(3) Rabbi Shimon says: Three who ate at one table and did not say upon it words of Torah - it is as if they ate from the offerings of the dead, as it is said (Isaiah 28:8): "For all of the tables are full of vomit and feces without the Omnipresent." However, three who ate at one table and said upon it words of Torah - it is as if they ate from the table of the Omnipresent, blessed be He, as it is said (Ezekiel 41:22): "And he said to me, this is the table that is before the Lord."

(4) Rabbi Chananya ben Chakhinai says: One who stays awake at night, and one who wanders on a road alone, and one who turns his heart to idleness, such a one is liable for [forfeiture of] his life.