This was asked a week or two ago, I answered it this way. :
Be aware that I'm not making judgement calls here but offering some simple direction. The book of Revelation was sewn together from Jewish mystic literature and very early christian exegesis of OT prophetics, later editors made some minor additions. The numbers are meaningful to the author as they carry astrological symbolism or represent gemetria (number for letter formulas). It is difficult to impossible to be certain what the author of Rev 14 intended as there were many ways of intrpreting gemetria (hence it's appeal) but here is one respectible attempt:
Aleph has the Kabbalistic value = 1
Daleth has the Kabbalistic value = 4
Mem has the Kabbalistic value = 40
So, 144 (or 144,000) is the number of Adam.
Adam is symbolic, it is in reference to Adam Kadmon, the Cosmos Human, the Heavenly Man.
Thus, Revelation 7:4 means that those who become the Adam Kadmon will enter Heaven.
Likewise, the Twelve Tribes represent the Twelve Zodical Signs under which the self realization of the Adam take place. The 12 foundation stones are the 12 'birth' stones of the lesser Jewish zodiac in correct order by month.