Rev 7:9

9 After these things I saw, and behold, a great multitude, which no man could number, out of every nation and of all tribes, peoples, and languages, standing before the throne and before the Lamb, dressed in white robes, with palm branches in their hands. 

a great multitude – the number was great. Why is this number great, or uncountable, versus the 144,000? It seems logical to think that the elect in the Sanctified Church are the chosen few, who receive the holy spirit, whereas, the elect of the Great Tribulation period were the great number who were justified by faith, and overcame by the word of their testimony.

which no one could count – the meaning here cannot simply be that no man was able to count such a great number. Rather, it is a contrast to those in the Sanctified Church who can be “counted.” For example, we saw 12 men counted in Acts 19:7, “were about 12 in all.” This is what distinguishes the Sanctified Church – the visible and audible evidence of being sealed by the holy spirit. However, those who were justified by faith, in the Great Tribulation, are known only to God.

palm branches – the palm branches that compare the Spirit of Christ, as “the Body of Christ,” entering New Jerusalem (Heaven) are compared to the palm branches that welcomed Christ, as “the son of man” to Jerusalem, in Matt 21:8.