@catholichodler @pipe @Aspartame @James Lewis @Fabiano 
The apostles were able to teach their doctrine out of the Old Testament, therefore it goes as follows
Old Testament -> church -> New Testament
As opposed to:
church -> Old and New Testament

You need to presuppose sacramentalism, there's nothing to imply they taught anything beyond OT doctrines with the clarification that Jesus is the Christ (Messiah) and that forgiveness is only found in Him, with baptism replacing circumcision, and the Lord's Supper replacing Passover.
At the council at Jerusalem, when debating over the necessity of circumcision and the law of Moses, they concluded that apart from abstaining from fornication, from meat offered to idols and from blood, there is no necessary burden to the Gentiles. If you needed the sacraments to be saved this'd be the time to ratify them.