What is the significance of the Greek word “sunerchomai”? Could it be significant that it does not appear in any post Acts 28 books?
The idea of the word seems to be “assembling together.” It is used a few times of journeying together. It is also used a few times of coming together in sexual union. It seems to me that it is a flexible word. It can mean simply assembling together, like the angry mob at Ephesus. Or it can have a more personal connotation, as of assembling together for a common purpose, or because of a common relationship.
It does not appear anywhere after I Corinthians. It occurs 8 times in the gospels, 16 times in Acts, and 8 times in I Corinthians. These are its only occurrences in Scripture. This would seem to stamp the number 8 upon this word. 8 is the number of new beginnings, as the eighth day begins a new week. This could have to do with the new beginning God was making at the time, in starting His kingdom upon earth.
Leaving externals, though, I don’t know that there seems to be anything internal to the word that would suggest something that could only happen in the Acts period. For example, anyone can journey together with someone else for a common purpose or goal. Anyone can assemble together for a common purpose, or even in confusion about what the purpose is. Everyone is capable of “coming together” in a sexual union. Only in the “coming together” of the ekklesia, such as in I Corinthians, could we see something that is not really possible today. This seems to refer to an assembly of the Corinthian leadership among the believers. This would be a unique thing to the Acts period, but not, I think, because of this word, but just because of the situation then, which was far different than it is today. It is really not possible for a “leadership body” to assemble together today, since there are no God-appointed leaders. I think it might be stretching the point, however, to try to find that in the meaning of this word.