Children of God does not make precise identification.
The children of God are the children of Israel - the Hebrews/Jews.
21 And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins.
Mt 1:21.
33 But this shall be the covenant that I will make with the house of Israel;
After those days, saith the LORD,
I will put my law in their inward parts,
And write it in their hearts;
And will be their God,
And they shall be my people.
Jer. 31:33.
The Old Testament are writings by Hebrews to and for Hebrews. From Pentateuch to Psalms to the Prophets, they were all written by covenant Hebrews to and for covenant Hebrews. The New Covenant writings are the same. They were all written Matthew to Revelation by Jewish Christians born again in the New Covenant era which is Israel's Messiah fulfilling the Mosaic Covenant and establishing the New Covenant in His blood. No longer did the children of Israel have to slay animals whose blood God used to atone for the sins of the children of Israel yearly as commanded by God until in the fulness of time God sent His Son, born or a woman under the Law to redeem those under the Law.
4 But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law,
5 To redeem them that were under the law, that we might receive the adoption of sons.
Gal. 4:4–5.
Thus, when and where the New Covenant writings refer to the "world" or "everyone" and the like, those designations identify the Hebrew people taken in context to whom the Word of God was written to.
God gives that which is holy (His Word) to holy people - the Children of Israel.
6 For thou art an holy people unto the LORD thy God: the LORD thy God hath chosen thee to be a special people unto himself, above all people that are upon the face of the earth.
Deut. 7:6.
God does not cast His Pearls (His Wisdom/Word) to swine.
Never has, never will.
