2 – It is recommended to use only the amount of water with which the Prophet ﷺ performed ablution, and the same rule applies to ghusl (the full ritual bath), for that was his guidance.

3 – Rubbing (dalk) the limbs during ablution is recommended because it is part of the desirable completion (isbāgh) of wuduʾ.

4 – Performed in this way, washing makes clear the difference between wiping (masḥ) and washing (ghasl): wiping means moistening the hand with water and passing it over the limb, whereas washing means letting water run over the part, even if the flow is slight.

5 – The optimal practice is to emulate the Prophet ﷺ in using approximately this quantity of water for ablution. A small additional amount does no harm, but wastefulness is forbidden. Aḥmad (6646) and al-Nasaʾi (140) relate from ʿAmr b. Shuʿayb, from his father, from his grandfather: “A Bedouin came to the Messenger of Allah ﷺ asking about ablution. He showed him three washings for each limb and said, ‘This is ablution; whoever exceeds this has behaved badly, transgressed, and wronged.’”

Scholarly disagreement
The jurists have differed over the ruling on rubbing: is it recommended or obligatory?
• Imām Mālik held it to be obligatory, using this hadith as proof.
• Imām Aḥmad held it is not obligatory, for nothing indicates compulsion; the Prophet’s own practice shows recommendation only, and the command concerns washing, not rubbing.
However, if water would not reach the skin without rubbing, then rubbing becomes obligatory—not on the strength of this hadith, but to ensure the obligatory thoroughness (isbāgh) and the completion of the ablution.