They themselves — i.e., the inhabitants of those countries. “Wherever we go we find our own story told us.”
Shew. — Rather, announce. Both sides of the story are told: (1) of us — what kind of entry we made among you, explained in 1 Thessalonians 2:1-12 to mean with “the word of truth, of meekness, and righteousness” (Psalms 45:5); (2) of you — how truly converted you were, as he proceeds to show further in 1 Thessalonians 2:13 to 1 Thessalonians 3:13.
Living and true God. — In contrast to the lifeless and false idols. The Thessalonians had been Gentiles, Perhaps St. Paul was thinking of his own speech on Mars Hill, which had been recently uttered.