According to evangelical Christian belief, the most likely author of Matthew 1:20-21 is the Apostle Matthew, also known as Levi. He was one of the twelve disciples chosen by Jesus to be part of his inner circle and is traditionally credited with writing the Gospel of Matthew.

Evangelical Christians believe that the Gospel of Matthew was written to present Jesus as the long-awaited Messiah and to communicate his teachings to a Jewish audience. The passage in question, Matthew 1:20-21, describes the angel Gabriel appearing to Joseph in a dream and explaining the miraculous conception of Jesus by the Holy Spirit. The angel tells Joseph that Mary will give birth to a son and that he is to be named Jesus because he will save his people from their sins.

Evangelical Christians view this passage as a fulfillment of Old Testament prophecies about the coming of the Messiah and as evidence of Jesus’ divine nature. They hold that Matthew, as an eyewitness to Jesus’ life and teachings, was uniquely qualified to accurately record these events and provide a reliable account of the life of Jesus.

Overall, evangelical Christians view Matthew 1:20-21 as an important part of the biblical narrative that highlights the miraculous nature of Jesus’ birth and his mission to bring salvation to humanity. They believe that the passage, along with the rest of the Gospel of Matthew, provides valuable insight into the identity and purpose of Jesus Christ.