Judaism may question Paul's belief in God as was practiced after the exile because of statements which are easily understood to state the deity of Christ (Romans 9:5, Titus 2:13, 2 Thessalonians 1:12, Ephesians 5:5, and Colossians 2:2). One educated as a Second Temple Jew should not make statements which could be taken to say Jesus was God. This is especially true for Paul who gave instruction to Gentiles, new to faith in God as revealed in the Old Testament.
Paul also makes statements implying deity in passages such as Philippians 2:6-11. It is unnecessary to include statements which many understand as declaring pre-existence to give instruction on the importance of humility.
Paul also makes statements which recall historical themes:
Galatians 1:3 (ESV, mGNT)
Grace to you and peace from God our Father and the Lord Jesus Christ
χάρις ὑμῖν καὶ εἰρήνη ἀπὸ θεοῦ πατρὸς ἡμῶν καὶ κυρίου Ἰησοῦ Χριστοῦ
The phrase θεοῦ πατρὸς ἡμῶν
, God our Father with respect to the Old Testament recalls YHVH choosing a people for Himself.
God as written in the LXX is usually with the article, and our God is specifically Israel's God. Second Temple Judaism understood "our" God who chose them created a distinction with those not chosen. In Romans Paul confronts the naive understanding of God choosing one group to reveal Himself to mankind (cf. Romans 3:29, and 9-11).
Paul's use of "our God" in addressing Gentiles implies he no longer holds to the Second Temple Judaism as he did before his conversion. Is this conclusion hermeneutically sound?
Additionally if one considers Father God and Lord Jesus Christ from the Christian perspective, then our Lord Jesus Christ is the distinction between Jew and Gentile.
Is it hermeneutically sound to understand Paul is using "Lord" and "our Lord" as Second Temple monotheism used "God" and "our God?" Is Paul using "Lord" in the universal sense as the Old Testament does with "God" and "our Lord" as with "our God?"