Accusation of fornication without proof is a heinous crime
17-8-2015 | IslamWeb
Question:
When I was a child, my mother used to host a man in her house, and it was known that the devil was their companion and tempted that man into having unlawful sexual intercourse with her. I was young and afraid of all things. I hate my mother and do not know what to do given the fact that she raised us after my father died. After I have grown up, this idea is continuously chasing me. I need a solution.
Answer:
All perfect praise be to Allaah, the Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is not permissible to say that so-and-so committed unlawful sexual intercourse depending on mere assumption, guessing, rumor, or groundless claims.
Islam has stipulated strict conditions for proving this crime. Imaam Ibn Rushd 
said: “Scholars have agreed that adultery/fornication needs to be proven by confession or the witness of four men. They held different opinions regarding proving it through the pregnancy of unmarried women if they claimed that they were forced (to practice it).” [Bidayat Al-Mujtahid]
He also said: "As for proving adultery through the testimony of witnesses, the scholars agreed that adultery can be proven through testimony and that the stipulated number of witnesses is to be four, as distinct from the number that is required for proving other rights. This is based on the saying of Allaah Almighty (which means): {And those who accuse chaste women and then do not produce four witnesses—lash them with eighty lashes and do not accept from them testimony ever after. And those are the defiantly disobedient.} [Quran 24: 4]."
The witnesses have to be described with being just. The validity of the testimony is contingent upon the witness having seen the man's penis inside the woman's vagina. Moreover, the testimony must be expressed explicitly, not implicitly or by indirect statements. Hence, it is obligatory for one to beware of accusing others without the availability of proof or confession. It will be even worse if one accuses his mother with this act based on mere guess or doubt. Add to this, it is a form of prohibited slander. Anyway, adultery/fornication is one of the grave major sins and has many bad repercussions in the worldly life and the Hereafter. It is obligatory on the one who has been afflicted with it to sincerely repent to Allaah Almighty and never to return to that sin. Assuming that this woman did actually commit fornication, then, perhaps she has repented of that. If this was the case, then it is good, otherwise, you have to advise her, enjoin her to do good, and forbid her from doing evil—with wisdom and good instruction. You should know that whatever violations the parents may commit, they never lose their rights on observing dutifulness towards them, regardless of the violation they committed, even if they reached the limit of disbelief. Allaah Almighty says (what means): {And We have enjoined upon man [care] for his parents. His mother carried him, [increasing her] in weakness upon weakness, and his weaning is in two years. Be grateful to Me and to your parents; to Me is the [final] destination. But if they endeavor to make you associate with Me that of which you have no knowledge, do not obey them but accompany them in [this] world with appropriate kindness and follow the way of those who turn back to Me [in repentance]. Then to Me will be your return, and I will inform you about what you used to do.} [Quran 31:14-15]
Allaah Knows best.