Peter, a traveling elder, had the ministry of a pastor and also of a teacher: 

Peter was set in as a pastor with authority in the pastor's ministry over the entire church. Peter was an apostle, a traveling ministry with universal authority who had the ministry of a pastor, a shepherd to care for the whole church.

• John 21:15-17 "So when they had dined, Jesus saith to Simon Peter, Simon, son of Jonas, lovest thou me more than these? He saith to him, Yea, Lord; thou knowest that I love thee. He saith to him, Feed my lambs.  He saith to him again the second time, Simon, son of Jonas, lovest thou me? He saith to him, Yea, Lord; thou knowest that I love thee. He saith to him, Feed my sheep.  He saith to him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said to him the third time, Lovest thou me? And he said to him, Lord, thou knowest all things; thou knowest that I love thee. Jesus saith to him, Feed my sheep. "

Let God be true and every man a liar.

Apostles are given the responsibility of protecting the entire flock of God from the attack of the enemy, but with so many voices in the world, each one claiming to be the one that should be listened to, how can you know? You are responsible to be close enough to God so that you can tell the difference between false apostles and real apostles.

Read the complete definition of "Apostle."