The Joy of Inductive Discovery (Greek)

I have been reading through the Greek New Testament once a year for the past several years. I enjoy it very much, and I think it helps me be a better teacher of Koine Greek, DUH!

This year I started off with the Gospel of John (easy), then I read John's epistles (easy), and from there went back to Matthew, at which time I will read straight through the New Testament, skipping over the books previously read.

First year students of New Testament Greek learn a couple pretty common deponent verbs as vocabulary:

πορεύομαι = I go
ἔρχομαι = I go, come

Students sometimes have difficulty with the concept of ἔρχομαι being either I come or I go. Which is it? In my reading today, included in the passage was the healing of the centurion's servant (Matthew 8:5-13). In v. 9 the centurion tells Jesus that he tells one servant to go and he goes, but to another one he says to come and he comes. Both words are used in that narrative:

καὶ λέγω τούτῳ· πορεύθητι, καὶ πορεύεται, καὶ ἄλλῳ· ἔρχου, καὶ ἔρχεται.

At least in this setting, πορεύομαι is the one meaning go, and ἔρχομαι means come. Now you ought to take this knowledge, add $3.50 to it, and be able to buy at least something at Starbuck's.