Baba Batra 93b — In Jerusalem there was a custom of displaying a flag in front of the door, thereby indicating that the meal was ready and that guests might come in and eat. The removal of the flag was a sign that the meal was finished and that guest should cease from entering.
Betzah 25b — A guest should not drink his goblet in one gulp. This is unmannerly.
Brachot 58a — Ben Zoma used to say, “What does a good guest say?” “How much trouble my host goes through for me. How much meat he has offered. How much wine he has set before me. How many cakes he has brought before me. And all of this trouble he went through for me.’” \"But an inconsiderate guest, what does he say?” “What trouble has my host gone through? I have eaten one piece of bread and a single piece of meat. I have had but one cup of wine. All the trouble the host has gone to has been only for his family.”
Iyov 31:32 — The stranger did not sleep in the street. I opened my doors to the traveler.
Rambam Hilchot Brachot 7:6 — Never embarrass your guests by staring at them.
