Following up on Joseph's reply, the Jews would have been fully aware of Psalm 2, and its references to the Son of God:
Psalm 2
PS 2:1 Why do the nations conspireand the peoples plot in vain?
PS 2:2 The kings of the earth take their stand
and the rulers gather together
against the LORD
and against his Anointed One. (=Messiah)
PS 2:3 "Let us break their chains," they say,
"and throw off their fetters."
PS 2:4 The One enthroned in heaven laughs;
the Lord scoffs at them.
PS 2:5 Then he rebukes them in his anger
and terrifies them in his wrath, saying,
PS 2:6 "I have installed my King
on Zion, my holy hill."
PS 2:7 I will proclaim the decree of the LORD:
He said to me, "You are my Son;
today I have become your Father.
PS 2:8 Ask of me,
and I will make the nations your inheritance,
the ends of the earth your possession.
PS 2:9 You will rule them with an iron scepter;
you will dash them to pieces like pottery."
PS 2:10 Therefore, you kings, be wise;
be warned, you rulers of the earth.
PS 2:11 Serve the LORD with fear
and rejoice with trembling.
PS 2:12 Kiss the Son, (remember the sinful woman of Luke 7:36-50?) lest he be angry
and you be destroyed in your way,
for his wrath can flare up in a moment.
Blessed are all who take refuge in him.
For the NT hearers/readers, the OT references to Son of God, Son of Man (Dan. 7:13-14, and various references in I Enoch), Messiah, Son of David, and King of Israel were attributed to Jesus.