'Children' in the Bible

The Spirit Himself testifies and confirms together with our spirit [assuring us] that we [believers] are children of God.

And if [we are His] children, [then we are His] heirs also: heirs of God and fellow heirs with Christ [sharing His spiritual blessing and inheritance], if indeed we share in His suffering so that we may also share in His glory.

that the creation itself will also be freed from its bondage to decay [and gain entrance] into the glorious freedom of the children of God.

and they are not all the children of Abraham because they are his descendants [by blood], but [the promise was]: “Your descendants will be named through Isaac” [though Abraham had other sons].

That is, it is not the children of the body [Abraham’s natural descendants] who are God’s children, but it is the children of the promise who are counted as [Abraham’s true] descendants.

and though the twins were not yet born and had not done anything either good or bad, so that God’s purpose [His choice, His election] would stand, not because of works [done by either child], but because of [the plan of] Him who calls them,