I just got started looking up the verses where Paul quotes from God and where he speaks as from God himself. Just read Romans to start with. Good grief! He begins the whole book starting with his authority to speak the gospel.
Romans 1
1Paul, a servant of Christ Jesus, called to be an apostle and set apart for the gospel of God— 2the gospel he promised beforehand through his prophets in the Holy Scriptures 3regarding his Son, who as to his human nature was a descendant of David, 4and who through the Spirit of holiness was declared with power to be the Son of God by his resurrection from the dead: Jesus Christ our Lord. 5Through him and for his name's sake, we received grace and apostleship to call people from among all the Gentiles to the obedience that comes from faith. 6And you also are among those who are called to belong to Jesus Christ. 7To all in Rome who are loved by God and called to be saints: Grace and peace to you from God our Father and from the Lord Jesus Christ.
Skip over to chapter 9 and we read:
1I speak the truth in Christ—I am not lying, my conscience confirms it in the Holy Spirit—
And that was just one book and a few verses in it. I think Mark gives us "busy-work" sometimes thinking he can get us frustrated and let him get away with saying whatever he wants without challenge. Wont work! Still like ya!
None of your excerpts are Paul quoting God as John does in Revelation, or the Gospel writers do. Why is this?