In Matthew 28:18-20 we read a very familiar passage of Scripture:
And Jesus came and spoke unto them (the disciples), saying, All power is given unto me in heaven and in earth. Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:

Teaching them to observe all things whatsoever I have commanded you: and, lo I am with you always, even to the end of the world.
Many times people have the mistaken idea that this commission was just for the disciples. That's not so. The Great Commission is addressed to believers—all believers.

You see, Jesus is actually saying the same thing here that He said in Mark 16:17-18. Mark translated His remarks this way:
And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; They shall take up serpents; and they shall drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
Mark is saying the same thing that Matthew said. The same commission is recorded in both places. The wording is just a little different. But you'll notice in Matthew 28 that, in the eyes of some people, it looks as though this is directed entirely to the disciples.

It is not. How do we know this is not just for the disciples, but for all believers? Because in Mark's version Jesus said that these signs shall follow them that believe.

Well, I'm one that believes, aren't you? Then the commission is for us, isn't it? It's for all those who believe on the Lord Jesus Christ—all believers. All of us are ambassadors for Christ, commissioned to carry the Good News to every creature.

Source: Sharing Jesus Effectively by Jerry Savelle.
Excerpt permission granted by Jerry Savelle Ministries International