“the Spirit.” In Ezekiel chapter 1, “The Spirit” occurs here in Ezekiel 1:12, and later in Ezekiel 1:20. We later learn that “the Spirit” is Yahweh (see commentary on Ezek. 8:2). God appears as “the Spirit” in Ezekiel 1:12, 20; 2:2; 3:12, 14, 24; 8:3; 11:1, 24).
[For more on the uses of “spirit,” see Appendix 6, “Usages of ‘Spirit.’”]
As many commentators point out, “the Spirit” (or “the spirit”) here in Ezekiel 1:12 has been interpreted many ways, including the wind, the Spirit of God, the spirit within the living creatures themselves, and the vital energy or impulse by which God, from His throne, acted upon them. However, since these cherubim carry God upon His throne, they would never go where they wanted to, they would always go where God wanted them to. Therefore we must understand “the Spirit” to be a reference to God here, and that is borne out in many other references in Ezekiel (cp. Ezek. 1:12, 20; 3:12, 14; 8:3; 11:1, 24; and see commentary on Ezek. 8:3).
“The Spirit” is not a reference to the preincarnate Christ or to a third member of the Trinity referred to as the Holy Spirit. Putting the whole multi-chapter vision that Ezekiel had together makes it very clear that the Spirit is Yahweh Himself.
[For more on why this Spirit could not be a preincarnate Christ, see Appendix 10, “Jesus is the Son of God, Not God the Son,” and for more on why it could not be a third member of the Trinity referred to as “the Holy Spirit,” see Appendix 11, “What is the Holy Spirit?”]
“They did not turn when they went.” They did not veer from their course; they traveled straight ahead (cp. Ezek. 10:11).