Many readers are misled by the idea
that angels were incapable of having sex. Indeed, according to Jesus, angels
neither marry nor are given in marriage (Luke 20:34 – 36). However, the
heavenly beings in Genesis 6 are not obedient but rebellious angels. They
aren’t acting according to their divinely given nature. As for their supposed
inability, no Israelite/Jewish reader would have thought of the angels as
incapable of sexual intercourse. Yes, they are spiritual beings, but they are
capable of taking on human appearance (see Gen 18 – 19; Mark 16:5). The
opposite idea is not a biblical one, but one produced by a faulty view on
angels developed during the Middle Ages when Christians thinkers were
influenced by a neo-Platonic philosophy that radically separated the spiritual
from the physical.
As I say, no ancient Israelite/Jew
would have adopted this perspective. Indeed, we know from the intertestamental
book 1 Enoch (see chs. 6 – 36) that many Jews read Genesis 6:1 – 5 in precisely
this way. Even more compellingly for the Christian reader, the author of the
book of Jude also understood the sexual transgression here as that between
humans and angels (Jude 6; see also 2 Pet 2:4). (Tremper Longman III, Genesis
[The Story of God Bible Commentary; Grand Rapids, Mich.: Zondervan, 2016],
114)