Acts 1

And they prayed and said, “You, O Lord, who know the hearts of all, show which of these two You have chosen  to take part in this ministry and apostleship from which Judas by transgression fell, that he might go to his own place.”  vv.24-25

Read chapter 1
Even after Jesus' earthly ministry there were still twelve specific apostles to carry out specific commissions from the Lord, different from just any disciple/believer of Jesus Christ.  We see and know there were many followers of Jesus and even in this choosing between Justus and Mathias it seems like a close tie of who'd be chosen among the twelve.  There is a difference in scripture when the word apostle is used verses when disciple is used.  Not all disciples are apostles and not necessarily all apostles are disciples (i.e. Judah Iscariot).  We have to discern in scripture what are specific commissions for these apostles and what are commissions for us as believers of Christ.  I know I'm excited to have a special commission one day from Jesus Christ but until then I'm not going to try to make some else's mine.  Yes we can learn from certain commission on how we can be in our mindset, actions or other ways but outcomes aren't always the same because it wasn't a specific sending of Jesus to us or our hope may whither if we don't see the same results we do in scripture.  The coolest thing to note is that Jesus elected the twelve before when He was here on earth and they want Him to elect the twelfth even when He's not physically present.  In what ways do you know you're a disciple of Jesus?  What are some specific apostleship commissions you see in scripture that are for a certain group or person?