The reading is from St. Paul's First Letter to the Thessalonians 2:9-14

Brethren, remember our labor and toil; we worked night and day, that we might not burden any of you, while we preached to you the gospel of God. You are witnesses, and God also, how holy and righteous and blameless was our behavior to you believers; for you know how, like a father with his children, we exhorted each one of you and encouraged you and charged you to lead a life worthy of God, who calls you into his own kingdom and glory. And we also thank God constantly for this, that when you received the word of God which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers. For you, brethren, became imitators of the churches of God in Christ Jesus which are in Judea.