John 17:18

As thou didst send me into the world, even so sent I them into the world.

Just as Christ delivered God's word, the apostles were instructed to deliver, not their word, but Christ's. This respect to the pattern of teaching illuminates the promise of Jesus that whatever the apostles bound on earth would be bound in heaven, etc. (Matthew 18:18). Not even the apostles had authority to set up an organization and teach whatever they might have conceived to be expedient or appropriate. They were to use the same fidelity in teaching what Christ commanded that Christ had used in declaring what God had said.

Even so sent I them ... This is prophetic tense, viewing the future sending of the apostles as already accomplished.