She swore a false oath; how can she expiate that?
Question

 
When I was four or five years old, I slept with my paternal uncle, and when I woke up I found a white liquid on my feet, like milk. I was scared of this thing. He was not married and was an adult. After I reached puberty, I began to practice the secret habit a great deal, and after that I found out that there is the hymen, and I was afraid that I had lost it (my virginity) because of my uncle. After I got married, I told my husband that someone had come to me and I did not know whether I had lost my virginity or not, and I swore falsely that I did not know this person and I said, May Allah never help me to succeed in anything if I know him. 
What is the ruling and do I have to offer expiation? Please note that I was afraid of problems, severing the ties of kinship and affecting my future. Now I am married and my virginity was intact, i.e., what I thought was wrong, and my uncle did not do what I thought he did, but I am not successful in any aspect of my life. What do you advise me to do?.
Praise be to Allah.Firstly: 
You have made several mistakes and you opened the door to waswaas and suspicion when you had no need of any of that. We do not know in fact what made you, at such a young age, interpret what you found on your body in a bad way that caused you a great deal of anguish, and opened your eyes to different kinds of sin, so that you did that evil action a great deal. We ask Allah to guide us and you and keep us chaste. 
You made another mistake and wronged yourself, your household and your husband, when you opened the dark pages of the past and cast a shadow over your life with your husband; you told him about something that he did not know and did not ask you about, to torment him along with yourself with doubt and speculation, and anxiety and suspicion about you and your situation. May Allah set your affairs straight. 
You made a third mistake by swearing a false oath when you had no need to do so and we do not think that it benefitted you at all. You prayed against yourself that you would not be helped to be successful, when you knew that it was a false oath, and now you are saying that you are not successful in your life. Your story is very strange, and there was no need for all of that. 
Now, the first thing that you must do is repent to Allah from all that you have done in transgressing the rights of your Lord, the rights of your own self and the rights of your husband and household. You have to strive, as much as you can, to set straight the things that have been spoiled by your bad conduct and failure to understand matters properly. Explain to your husband that what happened was no more than mistaken thinking and conjecture that was an illusion that turned out to be wrong, and you were the one who opened the doors to waswaas and speculation. 
Strive to let him see that you are a truthful and righteous person and try to prove to him through your conduct that you have some dignity, so that his mind will be put at rest concerning you and he may be happy with you. 
Secondly: 
With regard to the oath that you swore, saying that you do not know this person who did what he did, as you think, this is a false oath (al-yameen al-ghamoos). Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: It is called ghamoos because it immerses (taghmis) the one who does that in sin and then in Hell, because the one who knowingly swears a false oath concerning a matter that is in the past -- Allah forbid -- has combined two things: lying, which is one of the attributes of the hypocrites, and taking the matter of swearing an oath by Allah lightly, which is one of the attributes of the Jews, because the Jews are the ones who showed disrespect to their Lord, and ascribed shortcomings to Him, therefore it is an oath that immerses a person in the Fire."(Al-Sharh al-Mumti’, 15/130)
There is no expiation for this oath according to the correct scholarly view; rather what is required is to repent to Allah, may He be exalted, and seek His forgiveness. You must also beware of taking the matter of oaths lightly if you are telling the truth, so how about if you are lying?  
The Standing Committee was asked: 
I am a student in a Salafi Institute belonging to the Jamaa’at Ansaar al-Sunnah al-Muhammadiyyah in Kasla [?], and there is an Eritrean Muslim students union. There are major differences between the union and the jamaa’ah, hence doing activities with them is not allowed, but I participated with them. When the director of the institute found out, he asked me: Are you in the union? I said to him, No. He forced me to swear an oath so I did, but I was with them. Is this oath yameen ghamoos (a false oath) or do I have to offer expiation? Please note that if I had not been forced I would not have sworn an oath, but I regarded that as a case of necessity, because if I had told the truth he would have banned me from the Institute, and it is because of my keenness to seek knowledge that I did that. 
The Standing Committee replied: 
The oath that you mentioned was a yameen ghamoos, which is a major sin which cannot be expiated because of its seriousness. No expiation is prescribed for it according to the more correct of the two scholarly views; rather what is required is repentance and seeking forgiveness, so you have to repent and ask for forgiveness for it. End quote. Fatawa al-Lajnah al-Daa’imah, 23/133. 
Shaykh ‘Abd al-‘Azeez ibn Baz (may Allah have mercy on him) was asked: 
I have a brother who got a passport and he wants to get another one, and during the application process the official said to him: Do you swear that you do not have a previously issued passport? He did not see any Mushaf in front of the official, then the official took it out. My brother got scared and swore that he had not taken out any other passport. Please advise us on the ruling concerning this matter and whether he has to offer a sacrifice or is some other expiation sufficient? 
He (may Allah have mercy on him) replied: 
He has to repent to Allah, may He be glorified and exalted, just as any liar has to repent to Allah, and he has to be sincere in that and regret it, and not do it again. 
There is no expiation for a false oath according to the correct opinion. The expiation for vows has to do with those which refer to the future, for example if a person says “By Allah I will not do such and such” or “By Allah I will not speak to So and so.” As for the one who tells a lie, all he has to do is repent to Allah, regret what he has done and give up the sin, and he should sincerely resolve not to do that again, out of sincerity towards Allah and the desire for that which is with Him. Thus Allah will pardon him, because by means of sincere repentance Allah erases sin, as He says (interpretation of the meaning): “And all of you beg Allaah to forgive you all, O believers, that you may be successful” [Al-Noor 24:31]."(Majmoo’ Fatawa Ibn Baz, 23/115)
And Allah knows best.