You should follow the Sunnah and do not go beyond it.
جَاءَ أَعْرَابِيٌّ إِلَى النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ يَسْأَلُهُ عَنِ الْوُضُوءِ؟ فَأَرَاهُ ثَلَاثًا، ثَلَاثًا قَالَ: “هَذَا الْوُضُوءُ فَمَنْ زَادَ عَلَى هَذَا فَقَدْ أَسَاءَ، وَتَعَدَّى، وَظَلَمَ”
A Bedouin came to the Prophet ﷺ and asked him ﷺ about Wudu, so he ﷺ showed him (washing) three times, three times and then said. ‘This is the Wudu, whoever goes beyond it has erred, violated the limits and oppressed (his own self).’ (Ahmad 6684, Sahih).
When it comes to Wudu and Ghusl, we are not required to inspect every hair to make sure that it has become wet. Rather, we follow the Sunnah in terms of washing the parts of the body without falling prey to Waswasah. Dalk (rubbing the limbs after washing them) is part of the Sunnah and it can help to alleviate Waswasah.
In the Hadith above, we see that one is not to wash more than three times. Many people who fall prey to Waswasah go well beyond this, they contradict the Deen whilst thinking they are acting upon it by being cautious.
فَقَدْ أَسَاءَ ” أَيْ: بِتَرْكِ السُّنَّةِ ” وَتَعَدَّى “: أَيْ: حَدَّهَا بِالزِّيَادَةِ وَظَلَمَ: أَيْ: عَلَى نَفْسِهِ بِمُخَالَفَةِ النَّبِيِّ صَلَّى اللَّهُ تَعَالَى عَلَيْهِ وَسَلَّمَ، أَوْ لِأَنَّهُ أَتْعَبَ نَفْسَهُ فِيمَا زَادَ عَلَى الثَّلَاثَةِ مِنْ غَيْرِ حُصُولِ ثَوَابٍ لَهُ، أَوْ لِأَنَّهُ أَتْلَفَ الْمَاءَ بِلَا فَائِدَةٍ. (مرقاة المفاتيح شرح مشكاة المصابيح)
He has erred, meaning (erred) by leaving the Sunnah. Violated the limits, meaning he has increased upon it (the Sunnah). He has oppressed, meaning oppressed his own self by opposing the Prophet ﷺ, or he has fatigued himself by adding to the three (washes) without attaining any reward for himself, or because he has wasted water without benefit. (Imam Ali al-Qari, Mirqaat al-Mafateeh).
Becoming concerned that some parts of the body have not been washed without evidence, is Waswasah and we are obliged to turn away from it. So, as long as one follows the Sunnah, they should not be concerned with this type of investigation as it is from the Waswasah of Shaytaan.
For a more detailed discussion, please watch the video below.
– Answered by Shaykh Noorud-deen (21.04.2021)
See also (video):