As we get to Revelation 14 we have a series of four very short visions. The first of these involves the return of the 144000 Jewish men who are marked before in the book of Revelation. In this case, there is a picture of them on Mt. Zion worshiping God. In a sense you see that these 144000 have arrived in heaven and they are enjoying the fruits of their faithfulness to God.
For the Jewish believers in the seven churches. it would have had more meaning to understand that this could be them. That was something they would have understood and that they could have striven for themselves. There are tons of references back to the Old testament with this passage and it would have been a vision of their fulfillment.
The other thing that is that the timing of this vision could be present or future from the standpoint of the original readers. It could have been showing them 144000 Jewish men who had already ‘made it’ so to speak. It does not necessarily mean that we have to wait for this to be fulfilled and it could have been fulfilled in our lifetime as well. There is no timeframe in the book of revelation itself on this vision.
Next: Vision of Three Angels