I decided to read some of the Greek New Testament (off of my phone), while I was waiting. I remembered where I had left off, having finished Matthew 9, with the great passage on missions. I began reading in Matthew 10, where Jesus names the apostles, and then sends them out (Matthew 10:5). They were to go to the lost sheep of the house of Israel. When I got to Matthew 10:7, I thought, "Eureka! I have found it! The great lost "As you are Going!". Here is verse 7, just as I encountered it:
πορευόμενοι δὲ κηρύσσετε λέγοντες ὅτι ἤγγικεν ἡ βασιλεία τῶν οὐρανῶν.
The NIV text follows the Greek word order more closely than the ESV.
NIV: As you go, preach this message: ‘The kingdom of heaven is near.’
ESV: And proclaim as you go, saying, ‘The kingdom of heaven is at hand.’
The word πορευόμενοι is a present participle, usually translated as an -ing word. For years I have heard people assert that the Greek Commission text of Matthew 28:19-20 does not command people to Go! Usually they will identify the "go" word in the passage (πορευθέντες) correctly as a participle (though they seem not to recognize it as an aorist participle), and will state that there is only one imperative verb (make disciples), insisting that the participle (πορευθέντες) should be translated "as you are going."
As I stated earlier, I have heard this for years, usually from people who trained for the ministry at a sister school. The most recent time I heard it was over a year ago, when a prominent speaker (who trained for ministry at that school), made that same comment in a message in our chapel. I asked my boss if he could explain to me why people who studied there (have you guessed that I asked him because he went to graduate school there?) insist on making that false assertion. He speculated that it may have had to do with a very popular professor in the theology department that should have paid more attention to Greek before passing on wrong information (though he probably stated it with more grace that have I).
Concerning the Great Commission text, last year I found a document written by Daniel Wallace, author of the textbook we began using this year as our 2nd year Greek textbook. Last year, I made the article available to our 2nd year Greek students. Unfortunately, the document is no longer available on the web. If you would like to receive a copy of it, I can e-mail it to you, with the annotations I made.
As I continued reading into Matthew 11, I found another construction identical to the Great Commission structure--in Matthew 11:4:
πορευθέντες ἀπαγγείλατε Ἰωάννῃ ἃ ἀκούετε καὶ βλέπετε.
No Greek translator who knows what he or she is doing would dare render that verse as follows: "As you are going tell John what you hear and see." No! The clear meaning is "Go and tell John what you hear and see."
The grammatical structure is what Wallace calls attendant circumstance. Other grammars refer to this a coordinate circumstance. Daniel Wallace describes what happens:
The attendant circumstance participle is used to communicate an action that, in some sense, is coordinate with the finite verb. In this respect it is not dependent, for it is translated like a verb. Yet it is still dependent semantically, because it cannot exist without the main verb. It is translated as a finite verb connected to the main verb by and. The participle then, in effect, “piggy-backs” on the mood of the main verb. (Wallace, Greek Grammar Beyond the Basics, 640)
The participle "piggy-backs" on the mood of the main verb, being connected to the main verb semantically by the word and. So when a participle piggy-backs on an imperative verb, it gets imperatival force. We join them by the word and, which does not appear in the Greek text.
So, the Great Commission text does not say "As you are going . . .", but rather, "Go and make disciples . . ." Anybody who tells you differently has not read much Greek.