Lk 9:20
Many eyewitnesses and ministers of the word saw Jesus' works and his resurrection and wrote that Jesus was the Christ. Likewise, Luke communicated to Sir Theophilus that Jesus is the Christ through the Gospel of Luke. (Lk 1:1-4, Lk 9:20)
Lk 1:1 Forasmuch as many have taken in hand to set forth in order a declaration of those things which are most surely believed among us, 2 Even as they delivered them unto us, which from the beginning were eyewitnesses, and ministers of the word; 3 It seemed good to me also, having had perfect understanding of all things from the very first, to write unto thee in order, most excellent Theophilus, 4 That thou mightest know the certainty of those things, wherein thou hast been instructed.
Lk 9:20 He said unto them, But whom say ye that I am? Peter answering said, The Christ of God.