Assalaamu alaykum. I have been married for three months now. My wife was a Catholic and reverted to Islam, praise be to Allaah. When we got married, we did not have a ceremony, so my parents-in-law, who are not Muslim, planned one for us. So we went to their place and had a little party where we had food and chatted. The part that angered me is that my mother-in-law invited a priest so that he would pray for us. I told her that I cannot agree with that because he will be praying to Jesus as God, and she talked to him, and he said he would be using the word Lord to refer to God. I still did not agree with the idea. So in the middle of the ceremony, he had my wife and I stand and gave us two small candles and asked us to light a big candle that they call a 'unity candle' because they believe that when the bride and groom light that 'unity candle', they will never get divorced. It is all superstitious stuff that I do not believe in. After that, he started to pray for us and ask his "Lord" to give us blessings. I was repeating Istighfaar (asking Allaah for fogiveness) along with his prayer. So he was praying, and I was saying "Astaghfirullaah". My question is: did my wife and I sin when we both lighted that candle which they call a 'unity candle, and did we sin when that priest was praying for us, knowing that I was completely against the idea and I already told my mother-in-law that he could not pray for us? Also, my wife reverted not too long ago, and she was hiding her Islam from her family because she did not know how they would react. Please give us a fatwa. May Allaah reward you.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger. 

First of all, we congratulate your wife on having embraced Islam. We ask Allah to increase her in guidance and righteousness. We advise you to help her learn her religion and carry out righteous deeds and accompany her to good gatherings, and that you both treat each other with kindness; Allah, The Exalted, says (what means): {And cooperate in righteousness and piety, but do not cooperate in sin and aggression...} [Quran 5:2]

There is no doubt that the practices of priests are not void of polytheistic rituals, religious innovations, and superstitions. You did well by refusing to allow this priest to supplicate for you with words of Shirk (polytheism).

As for lighting the candle, if you knew that this was a ritual related to a religious innovation, you did wrong by obeying them in this regard. You should have refrained from participating in such a ritual, even if it meant upsetting others; verily, earning the pleasure of Allah is more important. ‘Aa'ishah, may Allah be pleased with her, said, “I heard the Prophet, sallallahu ‘alayhi wa sallam, say, ‘Whoever seeks to earn the pleasure of Allah by incurring people's wrath, Allah will suffice him from the people. And whoever seeks the people's pleasure by incurring the wrath of Allah, He will abandon him to the people.’” [At-Tirmithi]

The two of you must repent to Allah, The Exalted; please refer to fatwa 86527 about the conditions of repentance.

Allah knows best.