My MIL says that she was told by her brother(a priest) that the biggest sin is turning a person away from the Church. This is how she justifies supporting gay marriage.
This makes no sense to me, because if that we’re the case, how could the Church say that anything is sinful? It might turn someone away.
I know her opinion on this is wrong, but how do I explain that to her? How do I refute her position?
I wasn’t there, so I really can’t say what the priest told her. I’m guessing, he might have been saying, love the sinner, hate the sin. If she, is going to be in the Catholic Faith, she must follow the Teachings of the Catholic Church. You can not justify the action of sin, but we can have Charity(love), for the sinner. This might be, what she is confused about. By loving the sinner, does not condone there actions. Jesus, forgave the Adultress, when he said, he how has no sin cast the first stone.He, was not justifying her sin,but the people were judging her.He then said to her," GO AND SIN NO MORE!" We don’t judge the sinner, we love them, but we can not accept the sin.The Church, has the Authority from Jesus Christ, through the Holy Spirit, to guide all in such matters.Love, is the key to explaining, the Church"s Teaching, on Spiritual and Moral Matters.We are called, to love someone, that is Gay, but we are not called,to except the life style.I would seriously pray, for all involved here. Ask the Holy Spirit, to touch all of them ,and lead them back, to the teachings of the Church, which is guided by the Holy Spirit.Justifying Gay marriage, is justifying sin action,but we still love Gays, and pray for them, that is what I’d tell her.

God Bless and the Love and peace of the Holy Spirit be with you.