As far as Thomas\’ declaration, it seems pretty obvious that Thomas was not declaring Jesus to be the only true God.
Jesus himself tells us in the gospel of John that the Father = the only true God (17:3). Jesus tells Thomas just 11 lines earlier (20:17) that
God = the Father. Is one supposed to believe Thomas then turns around and contradicts Jesus? The narrator tells us 3 lines later the takeaway of his Gospel, and it is that Jesus = the Christ, the Son of God, not = the only true God.
Jesus doesn\’t congratulate Thomas on this heretofore unprecedented supposed declaration of his divinity (as he congratulates Peter on declaring him the Christ, the Son of God at Matthew 16:16).
Instead, Jesus chides Thomas on taking so long \’to believe\’. Believe what? Everything makes much more sense if Thomas\’ declaration is
\”My Lord [Jesus Christ] and my God [the Father],\” which then also fits into a broad pattern in the NT of pairing those terms that sort of way. Thomas gets it! That when he sees Jesus, he sees the Father (a basic teaching of John\’s Gospel, see John 12 and 14 in particular). One sees the Father when one sees Jesus because Jesus is the Christ, the Son of God – God\’s chosen agent or representative, who speaks the Father\’s word and does what the Father wants him to do. The resurrection is the proof of this – the sign which confirms everything Jesus claimed up to that point.
(The above is based on a post found on Twitter)
Here is a video for further explanation: