To make thine enemies thy footstool", as in Psalm 110:1, signifies to subjugate and keep under the hells. Here a footstool signifies the lowest region under the heavens -- that is to say, the hells. A footstool, as in Psalm 132:7, signifies the Lord's church in the earths.

(Referencias: Apocalypse Explained 607)

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.

(Referencias: Apocalypse Explained 10 [2]; Arcana Coelestia 2714)