This is a subsidiary post of Apostles.
The apostles were endowed by Christ with a teaching ministry. That is, in addition to testifying about the resurrection, they were to teach what Jesus had taught – and was teaching – them. In other words, they were sent to teach as well as to testify (The Twofold Function of the Apostles: Testifying and Teaching).
Matthew 28:18, 19, 20
1 Corinthians 14:18-19