Ibn Majah

1.
From this it is evident that in ablution (wudu), the feet must be washed; wiping (masah) is not sufficient.
Wiping is only permissible when socks or stockings have been put on while in a state of ablution, or if there is a wound on the feet and there is a risk of harm from water.

2.
The parts of the limbs of ablution where there is a possibility that water may not reach should be washed attentively so that they do not remain dry.
Similarly, during the obligatory ritual bath (ghusl), water should be made to reach those parts of the body attentively where there is a risk of them remaining dry.

3.
If some individuals in a group make a mistake, the better approach is to give a general warning or advice instead of mentioning their names; however, in some situations, it is more appropriate to warn them individually.

4.
Imam Bukhari rahimahullah has deduced from this hadith that washing the feet in ablution is obligatory, because the Companions radi Allahu anhum whom the Prophet sallallahu alayhi wa sallam rebuked had wiped over their feet during ablution and had not washed them. (Sahih al-Bukhari, Book of Ablution, Chapter: Washing the feet and not wiping over the feet, Hadith: 163; and Sahih Muslim, Book of Purification, Chapter: The obligation of washing the feet completely, Hadith: 241)

5.
A person of faith may also be subjected to the punishment of Hell due to some sin, but his punishment will not be eternal; however, the punishment of a disbeliever or polytheist will be eternal.

6.
The meaning of "wayl" is destruction and ruin.