There is not much mention made of “the Spirit of God,” but from what we are given in the text of Daniel we can identify Him as (i.)the Spirit of God, (ii.)the One who illuminates spiritual truth, (iii.)the One who gives wisdom and light and understanding to God’s elect. Regarding (i.), there is debate as to whether or not the Hebrew phrase should be translated as “the Spirit of God” or “the spirit of the holy gods.” The debate, I think, doesn’t really have a very strong exegetical foundation in light of the entirety of what the Scriptures teach. Translators who opt for the latter translation make textually unwarranted assumptions as to what the pagans who saw the Son of God and who identified the presence of the Spirit of God in Daniel could know about the God of the Hebrews. Rather than speculate as to whether or not these pagans knew about our Lord, I’d like to point to Genesis 41, where Joseph, much like Daniel who receives divine illumination from the Spirit, interprets the dreams of Pharaoh and provides him with wise counsel with respect to surviving the oncoming famine. In verse 38, Pharaoh exclaims: “Can we find a man like this, in whom is the Spirit of God?”
Pharaoh, a pagan, could recognize that the wisdom exhibited in Joseph was not of a human origin, nor did it have its origin in the gods of Egypt; Pharaoh knew that Joseph’s wisdom was given to Him by the Spirit of God Himself. The question that immediately comes to mind, therefore, is: If Pharaoh, a pagan if ever there was a pagan, could recognize the work of the Holy Spirit in the life of an individual, why do translators, of the ESV for instance, think that Nebuchadnezzar and Belshazzar could not also see that God’s Spirit was working in Daniel? The fact that the Spirit of God in Genesis 41:38 is spoken of in the same way in Daniel 4:8-9,18 & 5:11-12, moreover, is evidence in favor of translating the Hebrew phrase as “the Spirit of God.” We are given very important details about the role of the Holy Spirit that is also confirmed in many places in the Old Testament. Consider that the Spirit of God, in both Genesis 41 and Daniel 4 & 5, is the source of wisdom, light, and understanding, and He grants these gifts to particular individuals chosen for a specific task, and compare this concise description of His work in Joseph and Daniel with Exodus 31:1-5, 35:31; Numbers 11:16-30; 24:2; 27:18; Deuteronomy 34:9.
We could also look to even clearer passages regarding the Person and Work of the Holy Spirit in Isaiah 11:2 and Micah 3:8 for further confirmation of our belief that the Spirit of God in Daniel 4-5 is the Holy Spirit of God who is first mentioned in Genesis 1:2, who continually is present as the Person of the Godhead who indwells the people of God, grants them wisdom, light, and understanding, and shows them Christ. He is neither the Father nor the Son. He comes from the Father, for He is the Spirit of the Holy God, and He dwells in Daniel in order to illuminate his mind, granting him light and wisdom and understanding. As I’ve stated a few times, I’m not suggesting that Daniel had a complete understanding of the doctrine of the Trinity, although that idea is not entirely implausible; I am proposing that the book of Daniel contains the seeds of the doctrine of the Trinity. These seeds can be found and clearly grasped if we trace the leafy branches of New Testament Trinitarian doctrine back to their roots in the Old Testament instead of driving an unjustifiable historical a priori presupposition between the two. Praise be to the Ancient of Days, the Son of God/Son of Man, and the Spirit of the Holy God/Holy Spirit!
Soli Deo Gloria.