James R. Payton Jr. in Irenaeus on the Christian Faith:
[The apostolic] tradition taught that there was only one God, who created all things, formed humankind, and promised them deliverance after they fell into sin. The creation itself is good; indeed, the salvation achieved in Christ reclaims the entirety of creation, not just the immaterial realm. This savior is the Son of God, who came to fulfill the promises and prophecies of the Hebrew Scriptures; to do this, that Word genuinely became incarnate. In his body he suffered, died, and rose again from the dead. He empowered his disciples to become his heralds, and they trustworthily handed on what he had taught them. The apostles carefully instructed those who would follow them as leaders within the Church to assure a faithful transmission of the apostolic message.