Praise be to Allah.
Allaah says (interpretation of the meaning): " And if Shaytaan causes you to forget, then after the remembrance sit not in the company of those people who are the zaalimoon (polytheists and wrong-doers, etc.)." [al-An'aam 6:68]
Jaabir (may Allaah be pleased with him) reported that the Prophet (peace and blessings of Allaah be upon him) said: "Whoever believes in Allaah and the last day, should not sit at a table where wine is being served." (Reported by al-Tirmidhi, no. 2801; classed as saheeh in Saheeh al-Jaami', 6506).
Abu Sa'eed al-Khudri said: "The Messenger of Allaah (peace and blessings of Allaah be upon him) said: 'Allaah will ask His slave on the Day of Resurrection until He says: What prevented you, when you saw something evil, from denouncing it?'" According to another report: "One of you will be asked on the Day of Resurrection until he is asked: What prevented you from denouncing evil when you saw it?" (Reported by Imaam Ahmad and Ibn Maajah, 4017; see also Saheeh al-Jaami', 1818).
I think that now, my brother, you will know the ruling concerning going to parties where there is wine and other evils. When the believer sits in such gatherings it is as if his heart dies from merely seeing what is going on and saying anything about it, even if he himself does not partake of it.