Is it necessary to make water reach the site of an old wound on the head?

It is not necessary to introduce water into the strike when wiping the head, because those who advocate for wiping the entire head do not require water to penetrate it. Others have said that wiping part of the head is sufficient. This difference of opinion is based on the meaning of the letter "ba" (ب) in the phrase "wamasaḥū bi ru'ūsikum" (وَامْسَحُوا بِرُءُوسِكُمْ - and wipe your heads). Those who consider it an extra letter necessitate wiping the entire head, while those who consider it to indicate partiality necessitate wiping only part of it. The latter group has cited the hadith of Al-Mughirah: "that the Prophet (peace be upon him) performed ablution and wiped over his forelock and over his turban."