Foot
The foot, as in Deuteronomy 33:3, signifies an inferior principle. To set the right foot on the sea and the left on the earth, as in Revelation 10:2, signifies that the Lord has the universal church under His intuition and dominion.
(Riferimenti: Apocalypse Explained 10 [2]; Arcana Coelestia 2714)
Revelation 6:4
4
Another came forth, a red horse. To him who sat on it was given power to take peace from the earth, and that they should kill one another. There was given to him a great sword.