The 144,000 are the "FIRSTFRUITS/Woman/true Israel" (the Abrahamic/Jacob, Yeshua believing circumcised in heart) Jews redeemed by Christ who will flee into the wilderness for a time, times and a half-time (3^1/2 years of the Great Tribulation) from the great Red Dragon - Rev. 12:6.

Apostle Paul declared that all of Jacob's (Israel's) children were not the true Israel (the Woman)...ONLY the children of Promise.

Romans 9:6-8 (KJV)
⁶ Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel:
⁷ Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.
⁸ That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.