Enraged but exhausted in his fruitless attempts to destroy the woman, the dragon takes a stand on the seashore (Revelation 13:1/12:18). It’s a significant place for him to be,.
Going back to Genesis 1:2, we have a creation image. At the beginning, the Spirit of Yahweh hovered over the waters and brought a fruitful and orderly world out of the formless and void sea. Here, the dragon is beside the sea, and he also calls up a world from the sea, but it is an infernal, demonic world. It is an anti-creation, a counterfeit of creation.
Daniel 7 is also clearly in the background, as we will see as we go further through the passage. There, the four winds of heaven stir up the sea, and the sea produces a series of beasts. These are the four empires of the ancient world, called to be beast-guardians of Israel, as Israel exists within the oikoumene. Here it is not the four winds of heaven, which are the Spirit-inspired winds of the people of God, but the beast who calls up a beast from the sea. Again, we have a counterfeit of the original vision beasts that are not guardians of the saints but attackers.
The fact that he is on the “sand of the seashore” calls up a common promise from the Old Testament, first made to Abraham in Genesis 22:17 (cf. Genesis 28:14; 32:13; 41:49). Yahweh promised that Israel would become as numerous as the sand on the seashore, something that comes to pass in reality during the days of Solomon (1 Kings 4). The dragon stands on the sand, and that indicates his mastery of the people of God. That stance already foreshadows the coming vision of a land beast becoming an ally of the predatory sea beast.
Closer to the passage, we have scenes earlier in Revelation that resemble the scene of the dragon by the sea. When John first ascends into heaven, he sees a sea of glass like crystal stretching out before the throne of God. The Father is the “One Enthroned,” but then John sees the Lamb “standing as if slain” in the midst of the throne (Revelation 5:6). Though the text does not say it, it is consistent with the scene to suggest that the Lamb ascended through the heavenly sea to the throne. In cosmological terms, He would have to, since the sea is the upper side of the firmament that serves as a barrier between earth and heaven.
In chapter 10, a gargantuan angel descends from heaven and stands at the shore of the sea, right foot on the sea and left foot on the land. After the harvest of chapter 14, we see the saints who have come victorious from the beast standing on the sea (Revelation 15:2).
The Lamb is the first “beast” with horns and eyes to ascend through the sea, the heavenly sea. And when the dragon takes his position at the edge of the sea, and calls a beast from it, he is staking a divine position. The beast is a false Lamb, coming through the sea from the abyss as the Lamb broke the barrier of the heavenly sea to take the Father’s throne.