'Virtue' in the Bible

For if the inheritance [of what was promised] is based on [observing] the Law [as these false teachers claim], it is no longer based on a promise; however, God granted it to Abraham [as a gift] by virtue of His promise.

And we, [believing] brothers and sisters, like Isaac, are children [not merely of physical descent, like Ishmael, but are children born] of promise [born miraculously].