Is it obligatory to take new water for wiping over the leather socks (khuffayn), or is it sufficient to wipe with the water remaining from wiping the head and ears? And what is the most preponderant opinion on this matter?

The issue is based on the scholarly disagreement concerning used water. The majority of scholars hold that it is pure but not purifying, whereas some groups maintain that it is both pure and purifying. The evidence cited by those who affirm the purifying nature of used water was addressed by An-Nawawi, who either weakened it or interpreted it as referring to the second and third washings, which are supererogatory.

Based on this, if a person wipes their khuff (leather socks) with the residual water remaining on their hands after wiping their head, their purification is valid if it was the second or third wiping. However, if it was the first wiping, there is a dispute regarding the validity of their wiping. The more cautious approach is to avoid using used water for an obligatory purification to exit the disagreement of the majority of scholars.