Paul has more likely referencing the Jerusalem Temple.
The LORD is in his holy temple; the LORD’s throne is in heaven; his eyes see, his eyelids test the children of man.
Psalm 11:4 (ESV)
Identifying the temple of God as the believer portrays the relationship of God with his people via universal priesthood (cf. Hebrews 4:16; 1 Peter 2:9)
Do you not know that you are God’s temple and that God’s Spirit dwells
in you? If anyone destroys God’s temple, God will destroy him. For
God’s temple is holy, and you are that temple.
1 Corinthians 2:16-17 (ESV)
Paul may have been making a connection with what Jesus said in GJohn. The substance of the matter is that the Jerusalem Temple typifies the believers in whom God's Spirit dwells.Approaching God has never been like this -- so close and so unlimited.
21 Jesus said to her, “Woman, believe me, the hour is coming when
neither on this mountain nor in Jerusalem will you worship the
Father. 22 You worship what you do not know; we worship what we
know, for salvation is from the Jews. 23 But the hour is coming, and
is now here, when the true worshipers will worship the Father in
spirit and truth, for the Father is seeking such people to worship
him. 24 God is spirit, and those who worship him must worship in
spirit and truth.”
John 4:21-24 (ESV)