1 Corinthians 15:3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
Hebrews 9:28 So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation.
Hebrews 10:12 But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;
Ephesians 1:7 In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;
I know this was addressed to daniel1212. However, the quotes you gave were letters and not the sermons referred to in Acts.
1 Corinthians 15:3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
Again it appears you are not reading carefully what i said, as i made a distinction btwn sermons in Acts versus teaching to Christians, which is what your examples consist of. Though i do not see Paul as being the author of Hebrews (lacks his passion, etc.) but which is a key book.