It is unusual, but not impossible for servants to know what their master is doing. They are usually considered friends in Scripture if they have intimate knowledge of the things Jesus is doing. That is what it means to be friends at least, you share things that you don’t share with everyone with particular people. Nonetheless, we see Jesus doing that with his disciples and servants at the inauguration of his signs. The text of John 2:9–11 can be translated roughly something like this:
“But when the head steward tasted the water had become wine, he did not know where it came from, (though the servants drawing the water knew), he called the bridegroom. And he said, “every man first puts out the choice wine and when they have gotten drunk the inferior. You have guarded the best wine until now. In Cana of Galilee, Jesus did this as an inauguration of the signs, and clearly showed his [kingdom and priestly] glory, and his disciples trusted in him.”My translation from the NA 28 Greek Text
In the backdrop of John’s gospel is the fact that this is likely the only book written after the temple of Jerusalem has been destroyed. Thus, one can imagine the impact of these words and this inauguration of signs. The old water of Judaism, together with its customs and institutions, was inferior, the new wine of the priestly and kingly glory of Jesus is the best (cf. Murray J. Harris, John, Exegetical Guide to the Greek New Testament, 60). The book of Hebrews argues this case at its beginning, namely that Jesus is better than all things.
What is astounding here is the relationship being built on glory. The servants know something. The disciples also know something. And what they know is this: Jesus is better that what was former and inferior. They knew at the time of this miracle that Jesus Christ had guarded something for them that exceeded the glory of the temple and all of its customs. The kingdom of God was far more expansive,and God was sharing it with them as friends. So, we read “his disciples trusted in him.”
So, the friends of God know this about the kingdom: It’s the best, just like the King.