SBE 48: The Vedanta-Sutras with commentary by Ramanuja, George Thibaut, tr.: First Pâda: 27. And thus also, because thus only the designation of the beings...
27. And thus also, because (thus only) the designation of the beings, and so on, being the (four) feet is possible.
The text, moreover, designates the Gâyatrî as having four feet, after having referred to the beings, the earth, the body, and the heart; now this has a sense only if it is Brahman, which here is called Gâyatrî.