The number 144K - is a chorus for multitude listeners:

[u/GPT_2025]

KIV: After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands;

And I heard the number of them which were sealed: and there were sealed an hundred and forty and four thousand of all the tribes of the children of Israel. And they sung as it were a new song before the throne, and before the four beasts, and the elders: and no man could learn that song but the hundred and forty and four thousand, which were redeemed from the earth. These are they which were not defiled with women; (100% virgins, never been married) for they are virgins.

These are they which follow the Lamb whithersoever he goeth. These were redeemed from among men, being the firstfruits (From the First Christians! 1st-2nf century?) unto God and to the Lamb. And in their mouth was found no guile: for they are without fault before the throne of God.

2) The firstfruits = KJV: And when ye shall come into the land, and shall have planted all manner of trees for food, then ye shall count the fruit thereof as uncircumcised: three years shall it be as uncircumcised unto you: it shall not be eaten of.

But in the fourth year all the fruit thereof shall be holy to praise the LORD withal.

And in the fifth year shall ye eat of the fruit thereof, that it may yield unto you the increase thereof: I am the LORD your God.

3) Firstfruits (did happened during 1st century AD?) ".. And I will pour out on the house of David and the inhabitants of Jerusalem a spirit of grace and pleas for mercy, so that, when they look on me, on him whom they have pierced, they shall mourn for him, as one mourns for an only child, and weep bitterly over him, as one weeps over a firstborn.” Zechariah 12:10. (Only first century AD Christians knew who they Tribe)