Article 15: The means to Haram (unlawful) are forbidden if they most likely lead to Haram. But if there is a doubt that a means might lead to Haram, then this means will not be forbidden.
The evidence of this article is reflected in Allah’s (swt) saying
((وَلَا تَسُبُّوا۟ ٱلَّذِينَ يَدْعُونَ مِن دُونِ ٱللَّهِ فَيَسُبُّوا۟ ٱللَّهَ))
“And do not revile those they invoke other than Allah, lest they insult Allah in enmity without knowledge.” (TMQ 6:108). Insulting the disbelievers is permissible and Allah (swt) has insulted them in the Quran. However, if this insult were to lead the disbelievers to most probably insult Allah (swt), it would become prohibited. This is because insulting Allah (swt) is not permittedm and it is prohibited in the sternest fashion. This is how the Shari’ah principle, “the means to something forbidden is also forbidden”,has been deduced.However, the means becomes prohibited if it would most likely lead to something prohibited, since the prohibition of insulting their idols was because it was the cause which would lead to the insulting of Allah (swt) – as demonstrated by the use of the letter “fa” (lest) of causality in the verse, and if it was not most likely that Allah (swt) will be insulted because of insulting their idols, like the most likely probability (ghalabat Al-dhann) required in any Shari’ah rule, then the “fa” which indicates causality would not have been used to indicate the prohibition. Therefore, if the means were not considered in the most likely probability to lead to Haram but it was merely feared that it may lead to Haram, such as a woman going out without a face cover, where it is feared that it might cause Fitnah, the means in this case would not be Haram, because the mere fear that it might lead to Haram is not sufficient to warrant a prohibition. On top of that, the Fitnah with respect to itself is not prohibited upon the woman herself. This is the evidence of this article.
Another similar principle to this one is the following principle: “If one specific item of a Mubah thing leads to harm, that particular item becomes Haram and the thing remains Mubah”.This is reflected in what is narrated when the Messenger of Allah passed through the land of Al-Hijr and people took water from its well. When they left the Messenger of Allah said
«لاَ تَشْرَبُوا مِنْ مَائِهَا شَيْئاً، وَلاَ تَتَوَضَّؤُوا مِنْهُ لِلْصَّلاَةِ، وَمَا كَانَ مِنْ عَجِينٍ عَجَنْتُمُوهُ فَاعْلِفُوهُ الإِبِلَ وَلاَ تَأْكُلُوا مِنْهُ شَيْئاً، وَلاَ يَخْرُجَنَّ أَحَدٌ مِنْكُمُ اللَّيْلَةَ إِلاَّ وَمَعَهُ صَاحِبٌ لَهُ»
“Do not drink anything from its water and do not use it to make ablution for prayer. And whatever dough you prepared, give to the animals and do not eat anything from it. And no one goes out tonight but with a company.” reported by Ibn Hisham in his Sirah and Ibn Hibban in his Al-Thiqat. Drinking water is permitted, but that particular water, which is the water of Thamud, has been made prohibited by the Messenger of Allah because it led to harm. However, water in general remained permitted. Also, it is permitted for a person to go out at night without a companion, but the Messenger of Allah prohibited anyone from among that army, in that particular night and at that particular place, from going out because it led to harm. Apart from this, going out at night without a companion remained permitted. This serves as evidence that a particular item of the permitted thing becomes prohibited if it led to harm, while the thing in general remains permitted.