NET
8 This means it is not the children of the flesh who are the children of God; rather, the children of promise are counted as descendants.
Darby
8 That is, [they that are] the children of the flesh, these [are] not the children of God; but the children of the promise are reckoned as seed.
KJV
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.