A beast emerges from the sea and receives authority from the dragon. It enjoys a broad domain over the people of the earth and makes war on the people of God.
The beast from the sea is Satan’s agent on earth. Since Satan was pictured as a seven-headed dragon, the beast also has seven heads. The beast is the counterpart to the Lamb, who is the agent of God. Both the beast and the Lamb are said to have been slaughtered and yet returned to life, but there the similarities cease. Whereas the Lamb conquers by faithful suffering, the beast conquers by violent warfare. Whereas the Lamb redeems people of every tribe and nation, the beast oppresses people of every tribe and nation (5:5-10; 13:6-7). Readers living in New Testament times would have understood that the Lamb was a present reality for them. Similarly, they would have understood that the power of the beast was a present reality for them, and that this meant they were called to resist it.
The beast represents a form of tyrannical power that has operated at many times and places. An interpreter of dreams who was delivered from the lions' den.... More recounts a vision of various empires pictured as a lion, bear, leopard, and ten-horned monster (Daniel 7:1-8), yet all of these are included in the one great beast in Revelation. Moreover, the beast’s seven heads are later identified with the seven hills of Rome, indicating that the kind of threat posed by the beast was part of the world in which John’s first readers lived.
Many people refer to the beast as the antichrist, although that term is not used in Revelation itself. The popular depictions of the antichrist are created by combining various New Testament passages like pieces of a puzzle. The term antichrist comes from the Johannine Epistles (1 John 2:18, 22; 4:3; 2 John 7), although those passages refer to multiple antichrists. Some then attach this name to the beast of Revelation 13, and these passages are combined with references to “the lawless one” mentioned in 2 Thessalonians 2:3-10. This way of combining passages is part of some Christian interpretive traditions, but it includes many things that are not found in Revelation itself and goes beyond any particular biblical texts.