The final preparation phase included events that helped people accept the covenant. Some of the experiences were visual: lightning and a cloud (19:16), smoke and fire (19:18). The people also heard thunder, a ram’s horn, and the voice of God (19:16, 19). The entire mountain shook violently (19:18). In the Bible, such unusual events are often associated with a theophany, which is a visible appearance of God’s holy presence.