I like the way the Great Commission is stated in Mark, particularly as it is rendered in the KJV, namely, "...preach the gospel to every creature." In commanding the reader to do so, the text is not telling him or her to preach to every snail, lizard and iguana Dr. Doolittle-like, but to proclaim the gospel's life giving message to every single human being. That is a daunting task, even today, with the means of communicating that message so much more broadly than ever before.
It can be hard to wrap our heads around such a humungous task. It's so over-the-top, so all-encompassing, so out of reach, that it can become irrelevant. The temptation, I think, is to chalk it up to being just a theory that we never really anticipate becoming reality. Can you honestly say that the Great Commission smacks of reality and is thereby relevant to you?
If not, let me offer what may be a new way of looking at this mission to you. According to a modern statistical theory, any human being on the planet is separated from any other human being by a mere six degrees of separation. In other words, every person is networked to every other person by a maximum of six interpersonal links of association. According to this model, I know someone (1) who knows someone (2) who knows someone (3) who knows someone (4) who knows someone (5) who knows that one in consideration but who is unknown to me (6).
So how can we reach every creature with the Gospel? How were you reached? Doubtless, you became acquainted in some fashion with someone who knew Jesus. In making that connection, you were in a position to hear about Christ. I submit to you, then, that evangelism is, or should be thought of as, the process by which someone becomes connected to someone who knows Jesus.
In such a framework, the Great Commission becomes a task whereby the church lessens the degrees of separation that exist between one who does not know of Christ and one who does know Jesus. Our mission under such a regimen is to leapfrog the degrees of separation by sending people who do know Jesus into masses of people who do not know Jesus, until the degrees of separation between those of one class and those of the other reduce to one. Ultimately, that would give "every creature" an opportunity to hear about Jesus, and bring the Great Commission from the realm of fleetingly impossible into the realm of the probable.
The key to the Great Commission is to simply send people in the know into as many culturally distinctive groups who do not know as is possible and let them get to know people in that group and to share the gospel with them. If we do this at a great enough rate, ultimately, every single person alive will know someone who knows Jesus. Finishing the Great Commission is only a hare's breath away at that point. Tell me, are you sufficiently engaged in going and sending to make this happen in our age?