Most Bibles translate this verse like this:
And as he sat upon the mount of Olives, the disciples came unto him privately, saying, ‘Tell us, when shall these things be? and what shall be the sign of your coming, and of the end of the world?’
The words marked in bold, however, are likely spurious later additions (in other words, fake). We say this for three reasons:
1. The parallel accounts in Mark 13:4 and Luke 21:7 do not mention these words. It seems incredible that words asking about ‘the end of the world’ (or, as more correctly translated, ‘the end of the age’), would be left out from the other accounts.
2. The words are out of context (like most fake additions). The question was prompted by Jesus saying that the Temple would be destroyed. Up to this point in the conversation, nobody mentioned of Jesus coming in the future. Jesus later talks about a future coming in his answer, but there is nothing to indicate that the apostles had this in mind at the start. This explains why no such words are mentioned in Mark or Luke.
3. The ancient manuscripts that we have for the gospel of Matthew are the most varied and corrupted of all Bible manuscripts, and we have none of any useful length from before the 4th century. What happened to the text before the 4th century is really a black-box. Perhaps in the future we may discover manuscripts that allow us to restore the original Matthew. But as of 2021, we don’t have it yet. Therefore, any words that only appear in Matthew are automatically suspect. If anything else about them smells bad, then this increases our suspicion.
Therefore, we conclude that these provocative words are probably later fake additions to the text.
Like most spurious additions, they probably began life as a marginal note (or written between the lines) in a scroll used by a preacher. When scribes later copied the scroll, they didn’t know if the words were part of the original text or not. So, to play it safe, when making their copy, they moved the spurious words into main body of text. This copy was then copied again, until eventually, these words became ‘part of the Bible.’
Presence
One of these spurious words is a term usually translated as coming or nearness. However, Greek version is more correctly translated as presence. Adventist denominations take it to mean that Jesus will return in an invisible presence. However, we see this as a mistranslation of the original Aramaic. Please see the commentary, Coming, Presence, or Nearness for more information.