As far as Islam is concerned, there is nothing un-Islamic about using candles at a wedding so long as such a practice does not amount to extravagant spending. This is because such a practice is not a religious ritual but merely a custom, and the original rule in regards to customs is that everything is permissible unless otherwise proven. Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states: “The issue of using candles in wedding, eating while seated on chairs at tables or sitting on the floor, serving food on banana leaves or plates, et cetera, properly fall in the category of customs. They have no direct bearing on religion, and as such it is all left to the discretion of people. There is nothing un-Islamic about them so long as such a practice does not amount to extravagant spending. Should that be the case, then it would be considered either haram or undesirable since as Muslims we must stay away from an extravagant lifestyle. Allah says, “And do not be a wasteful squanderer, for the wasteful are the Devil’s brothers; and the Devil is ever ungrateful to his Lord.” (Al-Isra’: 26-27). We are not allowed to declare things as either haram (forbidden) or halal (lawful) based on our own personal whims and caprices; haram is that which Allah has declared as haram. The Prophet (peace and blessings be upon him) said, “Allah has enjoined certain duties, so do not neglect them. He has forbidden certain things, so do not commit them. He has set certain limits, do not transgress them. He is silent of many things, so do not inquire into them.”
In order to gain proper perspective on the distinction between pure customs and matters of religion, it would be insightful to remember what Imam Ibn Taymiyyah has pointed out: While the original rule in regards to religious rituals is prohibition, the original rule in regards to customs is that everything is permissible unless otherwise proven. This is because, according to the rules of Shari`ah, people are free to invent customs so long as these customs do not contradict any of the known principles or texts of the Shari`ah. In religious matters, however, they are allowed only to act based on clear sanction of revelation. In conclusion: don’t pick a fight over the issue of candles. You are allowed to go for it so long as it does not involve extravagant expenses.”