According to Matthew, the disciples of Jesus fell on their faces during the Transfiguration when

According to the Gospel of Matthew, the disciples of Jesus fell on their faces during the Transfiguration when Jesus' face shone like the sun. This happened when Jesus took Peter, James, and John up on a high mountain, and his appearance was transformed before them. His face shone like the sun, and his clothes became dazzling white. Then Moses and Elijah appeared before them and talked with Jesus. While they were still speaking, a bright cloud enveloped them, and a voice from the cloud said, "This is my Son, whom I love; with him I am well pleased. Listen to him!" It was at this point that the disciples fell on their faces out of fear and awe.