Q 1: I live in a village and most of its inhabitants are Muslims. They supplicate to people other than Allah in cases of calamities and adversities. They believe that prophets, Awliya' (pious people), martyrs and righteous people are near to Allah. (Part No. 7; Page No. 354) As for us, we commit sins and therefore we are not qualified to ask Allah without intermediation to Him through Awliya', martyrs and righteous people. These people claim that Awliya' drive us closer to Allah as they hear our supplication after their death and intercede for us to Allah. These people also organize festivals near the graves of righteous people. They call these festivals `Urs (weddings) and they vow exactly as disbelievers do in their temples. No one in my village holds the creed of the Salaf (righteous predecessors) except me. When I call them to the creed of the Salaf, they say that I am Mubtadi` (one who introduces innovations in religion) and Wahhaby. They mean that I follow Shaykh
Muhammad ibn `Abdul-Wahhab
(may Allah be merciful to him). If the creed of those people is as I have mentioned, can I perform Salah behind them or should I perform Salah alone? Am I permitted to eat from the animals they slaughter?
You are not permitted to perform Salah behind those who hold these creeds. If you perform Salah behind them, your Salah will be invalid. They commit polytheistic acts that render them Mushriks (those who associate others with Allah in His Divinity or worship). You are also not permitted to eat from the animals they slaughter because they are Mushriks due to legal proofs reported in this regard. We ask Allah to keep you firm on the truth and to guide them by your help in order that you may receive the like of their rewards if they follow your advice. We recommend you to go on calling them to Allah and in guiding them to the truth with good means and a fine and effective way. You also have to bear their harms patiently. Allah (Glorified and Exalted be He) says: (Part No. 7; Page No. 355)
Invite (mankind, O Muhammad صلى الله عليه و سلم) to the Way of your Lord (i.e. Islâm) with wisdom (i.e. with the Divine Revelation and the Qur’ân) and fair preaching, and argue with them in a way that is better.
Allah (Glorified be He) told us that Luqman said to his son:
"O my son! Aqim-As-Salât (perform As-Salât), enjoin (on people) Al-Ma‘rûf - (Islâmic Monotheism and all that is good), and forbid (people) from Al-Munkar (i.e. disbelief in the Oneness of Allâh, polytheism of all kinds and all that is evil and bad), and bear with patience whatever befalls you. Verily, these are some of the important commandments (ordered by Allâh with no exemption).
There are many Ayahs (verses) and Hadiths that deal with this topic.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.