Romans 1:9,16
For God is my witness, whom I serve with my spirit in the gospel of his Son, that without ceasing I make mention of you always in my prayers;
Torrey's Topical Textbook—AKJV

2 Corinthians 2:12
Furthermore, when I came to Troas to preach Christ's gospel, and a door was opened to me of the Lord,
Torrey's Topical Textbook—AKJV

1 Thessalonians 3:2
And sent Timotheus, our brother, and minister of God, and our fellow laborer in the gospel of Christ, to establish you, and to comfort you concerning your faith:
Torrey's Topical Textbook—AKJV