There has been a lot of confusion over who the 144,000 will be and why they will be chosen.
Here I will try to unravel some of the confusion, not all as a lot of it is still shrouded in mystery (to me).
Revelation 14:3-5 (KJV)
3 - '........but the hundred and forty four thousand which were redeemed from the earth.
4 - These are they who were not defiled by women; for they are virgins. These are they which follow the Lamb withersoever he goeth. These were redeemed from among the men, being first fruits unto God and the Lamb.
5 - And in their mouth were found no guile: for they are with out fault before God.
When we read 'woman' or 'women' this is not referring to biological females - The Church is the 'Bride of God' and therefore is referenced in the feminine.
Reference - 'not defiled by women; for they are virgins' - they are not 'virgins' in the sexual sense, they have not been 'defiled' by the false teachings of the apostate church and have remained true to the Teachings of Christ and the Laws of God. Man has given us many laws, but God only gave us TEN. I read the bible and do my best to sort the wheat for the chaff.
So if we go to:
Revelation 18:4 - And I heard another voice from heaven, saying, Come out of her, my people, that ye be not partakers of her sins, and that ye receive not of her plagues.
God is telling us to stay away from the apostate Church, do not listen to, or follow the 'laws of man', 'Come out of her (the church) my people'.
'in their mouth was found no guile' they did not preach the false doctrines of the church, they did not listen to, or follow the laws of man, but followed the Word of the Lamb and therefore 'found without fault before the throne of God'.