Who are the "Sons of God"? Why are they called sons of God?

6 On what were its bases set,
or who laid its cornerstone -
7 when the morning stars sang in chorus,
and all the sons of God shouted for joy?Job 38:6-7

Mormonism teaches that we are all brothers and sisters to Jesus and Satan. When God created the world and set in motion the plan of salvation, Mormons claim that we all (the supposed sons of God) rejoiced, and such is their interpretation of this verse. They use Job 38:6-7 as a proof-text for their doctrine of pre-existence (we all existed as God's spirit children before this world was created). As with most things, Mormons are wrong. The phrase "sons of God" in Job 38 is a reference to angels.

The sons of God are those born of the Spirit

As noted above, the truth is that the "sons of God" mentioned in Job 38 are, in fact, angels. The phrase itself is not arbitrary or abstract, but has a specific meaning. Only those born directly of God are called "children" or "sons" of God.

What is born of the flesh is flesh, and what is born of the Spirit is spirit.John 3:6

This is why angels are called "sons of God". This is why Adam is called "Adam, the son of God" (Luke 3:38). This is why Christ is called the "Son of God" (Luke 22:70; 8:28, John 3:18; 11:27). This is why Christians are called "children of God"--because they have been "born from above", directly by God (1 Corinthians 5:17, Ephesians 2:10).

Old Testament references

In the Old Testament, the original text meaning "sons of God" (some form of beney ha'elohim), though translated in various ways, always refers to Angels. The context of each occurrance suggests this, and it makes sense since the other "sons of God" (Jesus, Christians, Adam) are not being dealt with in these verses.

1 When humankind began to multiply on the face of the earth, and daughters were born to them, 2 the sons of God saw that the daughters of humankind were beautiful. Thus they took wives for themselves from any they chose. 3 So the LORD said, "My spirit will not remain in humankind indefinitely, since they are mortal. They will remain for 120 more years."
4 The Nephilim were on the earth in those days (and also after this) when the sons of God were having sexual relations with the daughters of humankind, who gave birth to their children. They were the mighty heroes of old, the famous men.Genesis 6:1-4 (see Who are the nephilim? for more on this passage)

When the Most High gave the nations their inheritance,
when he divided up humankind,
he set the boundaries of the peoples,
according to the number of the heavenly assembly.Deuteronomy 32:8

Now the day came when the sons of God came to present themselves before the LORD - and Satan also arrived among them.Job 1:6

4 "Where were you
when I laid the foundation of the earth?
Tell me, if you possess understanding!
5 Who set its measurements - if you know -
or who stretched a measuring line across it?
6 On what were its bases set,
or who laid its cornerstone -
7 when the morning stars sang in chorus,
and all the sons of God shouted for joy?"Job 38:4-7

Acknowledge the LORD, you heavenly beings,
acknowledge the LORD's majesty and power!Psalms 29:1

5 O LORD, the heavens praise your amazing deeds,
as well as your faithfulness in the angelic assembly.
6 For who in the skies can compare to the LORD?
Who is like the LORD among the heavenly beings,Psalms 89:5-6

Again, the Old Testament occurrences clearly refer to angelic beings. There is no reason to assume otherwise, and when Mormons do so, they are taking a false meaning from their religion and forcing it upon the Biblical text without warrant.