he said: “O Allah, wash me of my sins with water, snow, and hail.”
Thus, what appears to be meant is that the first phrase concerns keeping one at a distance from sins—that is, that I do not commit them. Then, if I do commit them, cleanse me of them; then remove their effects through further purification with water, snow, and hail. Water is undoubtedly cleansing, but the relevance of snow and hail here is that the consequence of sins is punishment in the Fire, and the Fire is hot; therefore, what is cool is suited to cleansing one from it. Water cleanses, while snow and hail cool.
This is the meaning of the hadith of Abu Hurayrah, may Allah be pleased with him. It remains to be asked: can an error occur on the part of the Prophet ﷺ?
The answer is that the Prophet ﷺ said, “O Allah, wash me of my sins,” thus attributing sins to himself. He would also say: “O Allah, forgive me all my sins: the small and the great, the first and the last, the open and the secret.” (1) Allah Most High says:
“And seek forgiveness for your sin, and for the believing men and believing women.” [Muhammad 47:19]
And Allah says:
“So that Allah may forgive you your past and future sins.” [al-Fath 48:2]
But the crucial question is whether such sins remain or not.
The answer is no. The Prophet ﷺ is protected from persisting in sin, and he is forgiven, unlike others: a person may sin, may be left to persist in it and continue in his disobedience, and may not be forgiven. As for the Prophet ﷺ, he must be alerted to it, whatever the matter may be:
“O Prophet, why do you forbid what Allah has made lawful for you, seeking the pleasure of your wives? And Allah is All-Forgiving, Most Merciful.” [al-Tahrim 66:1]