The meaning of the saying of the Prophet, Allah’s blessings be upon him and his Family: «May Allah curse the one who performs a sin or gives refuge to a sinner»

I heard him say: The Messenger of Allah, Allah’s blessings be upon him and his Family, cursed the one who performed a sin in Medina or gave refuge to a sinner. I said: And what is that sin? He said: Murder.

The Messenger of Allah, Allah’s blessings be upon him and his Family, said: The one who performs a sin or gives refuge to a sinner, upon him is the curse of Allah, the Angels and the people, all of them. Ransom and…