For Marriage
This marriage is not in your best interest (Salah); you will be held back from your Deen. If you only seek appearances, do not do it; it is by no means advisable.
For Business / Deal
You will fall into Haram and gain no benefit whatsoever; definitely abandon it.
قُلْ يَا أَهْلَ الْكِتَابِ لَا تَغْلُوا فِي دِينِكُمْ غَيْرَ الْحَقِّ وَلَا تَتَّبِعُوا أَهْوَاءَ قَوْمٍ قَدْ ضَلُّوا مِن قَبْلُ وَأَضَلُّوا كَثِيرًا وَضَلُّوا عَن سَوَاءِ السَّبِيلِ
Qul ya ahla alkitabi la taghloo fee deenikum ghayra alhaqqi wala tattabiAAoo ahwaa qawmin qad dalloo min qablu waadalloo katheeran wadalloo AAan sawai alssabeeli
Say: "O people of the Book! exceed not in your religion the bounds (of what is proper), trespassing beyond the truth, nor follow the vain desires of people who went wrong in times gone by,- who misled many, and strayed (themselves) from the even way.
