Daniel 7:7
7 “After these things, as I was watching in the night visions a fourth beast appeared—one dreadful, terrible, and very strong. It had two large rows of iron teeth. It devoured and crushed, and anything that was left it trampled with its feet. It was different from all the beasts that came before it, and it had 10 horns. 8 “As I was contemplating the horns, another horn—a small one—came up between them, and three of the former horns were torn out by the roots to make room for it. This horn had eyes resembling human eyes and a mouth speaking arrogant things. 9 “While I was watching, thrones were set up, and the Ancient of Days took his seat. His attire was white like snow; the hair of his head was like lamb’s wool. His throne was ablaze with fire, and its wheels were all aflame.
Revelation 12:3
1 Then a great sign appeared in heaven: a woman clothed with the sun, and with the moon under her feet, and on her head was a crown of twelve stars. 2 She was pregnant and was screaming in labor pains, struggling to give birth. 3 Then another sign appeared in heaven: a huge red dragon that had seven heads and ten horns, and on its heads were seven diadem crowns. 4 Now the dragon’s tail swept away a third of the stars in heaven and hurled them to the earth. Then the dragon stood before the woman who was about to give birth, so that he might devour her child as soon as it was born. 5 So the woman gave birth to a son, a male child, who is going to rule over all the nations with an iron rod. Her child was suddenly caught up to God and to his throne,
Notes and References
"... The term Leviathan occurs only six times in the Hebrew Bible (Isaiah 27:1; Psalm 74:14; 104:26; Job 3:8; 40:25. In all these instances the Septuagint renders it “dragon, sea-serpent,” with the exception of Job 3:8 where the translators have chosen “the great sea monster,” probably because they wanted to connect this text with Genesis 1:21 where the Septuagint has “the great sea monsters”. Also the great fish that swallowed Jonah becomes a great sea monster in the Septuagint (Jonah 2:1; compare 11). The author of the New Testament book of Revelation seems to have taken over this Greek reinterpretation of the Hebrew name of the monster (“a great dragon” in Revelation 12:3; see also verses 4, 7, 9, etc.). Remarkably enough this great dragon of Revelation 12:3 has seven heads and ten horns. The ten horns seem to have been derived from the description of a terrifying monster in Daniel 7:7. But where did the seven heads come from? True, Psalm 74:14 attributes “heads” (plural) to the Leviathan, but the number “seven” is lacking there. In Revelation 12:9 and 20:2 the great dragon is identified with “the ancient serpent, who is called Devil and Satan, the deceiver of the whole world.” It is generally assumed that this is a reference to Genesis 3, which would imply that the author of Revelation entertained a macrocosmic idea of the serpent in Eden ..."
Korpel, Marjo and Johannes de Moor "The Leviathan in the Ancient Near East" in Bekkum, K. van (ed.) Playing with Leviathan: Interpretation and Reception of Monsters from the Biblical World (pp. 3-18) Brill, 2017