‘Abdallah b. Mas'ud reported God’s Messenger as saying, “No man who acquires unlawful property and gives some of it in alms will have it accepted from him; neither will he receive a blessing for it if he con-tributes some of it; and if he leaves some of it behind him (i.e. when he dies) it will be his provision for hell. God does not obliterate an evil deed by an evil one, but He obliterates an evil deed by a good one. What is impure does not obliterate what is impure.” Ahmad transmitted it, and the same is given in Sharh as-sunna.