Nikaah & Marriage Issues

Marrying a chaste woman after committing zina

Q: I got into a debate with a person who has quoted from the Quraan about the topic on fornication. She stated that according to her understanding of the verses, a fornicator, even if they have repented cannot marry a pure person and if they do then the nikkah will not be valid. I debated that Allah Ta'ala forgives the sincere repenter so how can they be punished if they go on to marry a virgin etc. Please shed some light, was I right in my reply?

Will hurmat-e-musaaharah be established through sodomy

Q:

1. If a son and father commit sodomy with each other, is it permissible for the son's (who committed sodomy with his father) children/grandchildren to marry his brother's/sister's children/grandchildren?

2. (A) committed sodomy with (B). Will (A)'s sister be allowed to marry (B)'s brother? Or Will (A)'s brother be allowed to marry (B)' sister?

3. (A) committed sodomy with (B). Is it permissible for (A) to marry (B)'s own sister/cousin?

4. If someone committed sodomy with his male cousin/male cousin's son. Are their children/grandchildren allowed to marry each other?

5. If someone touched his female cousin or his female cousin's daughter/male cousin's daughter with lust. Are their children/grandchildren allowed to marry each other?

Exchanging of gifts on the occasion of nikaah

Q: I heard from the honorable Ulama a hadith regarding nikah. Nabi Muhammad (صلى الله عليه وسلم) said: 

أعظم النكاح بركةً أيسره مؤنةً

The most blessed nikah is the one which carries less expense.

So in this hadith Nabi (sallallahu alaihi wasallam) encouraged the ummah to spend the least on the occasion of nikah. I would like to ask you a few questions regarding the 'Money Spent' in Nikah.

1. What type of expense is referred to in this hadith that should be kept least to achieve the maximum barakah (benefit) of nikah?

2. Does giving gifts such as clothing, perfumes, etc. to the groom's family before the nikah ceremony fall under the category of nikah expenses as mentioned in the hadith?

3. Does holding a feast for the groom's family and brides close relatives after the nikah, at the time of rukhsati, fall under the category of 'nikah expenses' as mentioned in the hadith?

4. Does gifting the groom's family with garlands, flowers, and sweets after the nikah as a way to express happiness fall under the category of 'nikah expenses mentioned in the hadith above?

5. Should all these activities mentioned above be avoided to achieve the blessings of nikah?

6. If the bride's father is wealthy enough to carry out the expenses of such activities like giving gifts, holding feasts, etc. and does it happily without having the niyah to show off but just to express happiness,will this approach be against the hadith of Nabi (sallallahu alaihi wasallam) that encourages us to spend the least on the occasion of nikah?