John 14:2 is a well-known and loved line attributed to Jesus: “In my father’s house there are many mansions” (KJV). There are many pastoral illustrations using the idea of a “mansion in glory. Usually someone turns up in heaven and finds that they have a small starter home instead of a glorious mansion and the Lord tells him “you didn’t send ahead any good building material.” The idea of a heavenly mansion turns up in hymns, including the classic Victory in Jesus: “I heard about a mansion He has built for me in glory…”
The Greek word used here (μονή) simply means a place to live, either a stopping place on a journey or a home. It is used for an apartment in a larger building. The translation “mansion” is based on the Latin Vulgate, the Latin word mansiones means more or less the same thing, but the English cognate usually means a grand home, a palace-like structure of some kind. Since the idea of God living in a mansion resonates with most people, “many mansions” has stuck in the imagination.
But what would “in my father’s house are many mansions” mean? That God has a vast Mansion, and the disciples will have mini-mansions within it? That Heaven is alike a big place, like Versailles? This is likely not the point.
Hearing this metaphor in the world of the first-century, especially within the world of a Galilean Jew, will help understand it better. Most families were patrilocal, meaning they would live with their father’s family as mich as possible. When a son got married, he would build a house on his father’s property, creating a common courtyard. It is possible that he would begin my adding a room on to his father’s house. Within the world of the metaphor, then, Jesus is going to return to the father’s house and expand the father’s house so that there is room for the new residents who will soon join him.
It is likely that this is a marriage metaphor, since the most obvious reason that a man would expand his father’s house would be to bring his bride home to live there. The point is that Jesus is going to prepare a place in the presence of God for his disciples.
Since he has gone to prepare a place, the disciples can be assured that Jesus will return for them (v. 3b-4). If this is a marriage metaphor, then it is obvious to the original audience that the departure of Jesus (the bridegroom) will result in his return to collect his bride (the disciples). That is the way these things work, a separation of the engaged couple is normal, the husband to be goes off to prepare a place for his bride to live after they are married.
This use of a marriage metaphor is not a surprise, since Jesus’ first sign is at a wedding banquet. Israel often thought of itself as the wife of the Lord, and that the marriage went very badly. She was unfaithful and was sent away into the wilderness of the Exile. But rather than divorce his wife, the Lord will restore her at the beginning of the new age. Hosea and Jeremiah 2-4 expect the restoration of Israel and Judah at some time in the future, when God will recall his wife from her exile and restore the marriage “as it once was.”
Jesus very clearly tells his disciples that his departure (the death, resurrection and ascension) is not the end of the story, he will return to “bring them home.”