The interpretation timeline
Daniel 3:25 Douay-Rheims

Then Azarias standing up prayed in this manner, and opening his mouth in the midst of the fire, he said:

A.D. 202 – 1871 6 witnesses

Patristic

before A.D. 750
202
A.D.
Irenaeus Patristic
c. A.D. 130–202
“If, then, neither Moses, nor Elias, nor Ezekiel, who had all many celestial visions, did see God; but if what they did see were similitudes of the splendour of the Lord, and prophecies of things to come; it is manifest that the Father is indeed invisible, of whom also the Lord said, "No man hath seen God at any time." But His Word, as He Himself willed it, and for the benefit of those who beheld, did show the Father's brightness, and explained His purposes (as also the Lord said: "The only-begotten God, which is in the bosom of the Father, He hath declared [Him];" and He does Himself also interpret the Word of the Father as being rich and great); not in one figure, nor in one character, did He appear to those seeing Him, but according to the reasons and effects aimed at in His dispensations, as it is written in Daniel. For at one time He was seen with those who were around Ananias, Azarias, Misael, as present with them in the furnace of fire, in the burning, and preserving them from [the effects of] fire: "And the appearance of the fourth," it is said, "was like to the Son of God." At another time [He is represented as] "a stone cut out of the mountain without hands," and as smiting all temporal kingdoms, and as blowing them away (ventilans ea), and as Himself filling all the earth. Then, too, is this same individual beheld as the Son of man coming in the clouds of heaven, and drawing near to the Ancient of Days, and receiving from Him all power and glory, and a kingdom. "His dominion," it is said, "is an everlasting dominion, and His kingdom shall not perish."”
Source
235
A.D.
Hippolytus of Rome Patristic
c. A.D. 170–235
“"And the form of the fourth is like the Son of God." Tell me, Nebuchadnezzar, when didst thou see the Son of God, that thou shouldst confess that this is the Son of God? And who pricked thy heart, that thou shouldst utter such a word? And with what eyes wert thou able to look into this light? And why was this manifested to thee alone, and to none of the satraps about thee? But, as it is written, "The heart of a king is in the hand of God: "the hand of God is here, whereby the Word pricked his heart, so that he might recognise Him in the furnace, and glorify Him. And this idea of ours is not without good ground. For as the children of Israel were destined to see God in the world, and yet not to believe on Him, the Scripture showed beforehand that the Gentiles would recognise Him incarnate, whom, while not incarnate, Nebuchadnezzar saw and recognised of old in the furnace, and acknowledged to be the Son of God.”
Source
date
unknown
c. A.D. 400
“Nebuchadnezzar, having ordered the three men to be cast into fire, saw a fourth when he looked into the furnace and said, "I see the fourth as the Son of God." He was impious and yet saw apparitions, visions and dreams. Thus, we cannot infer with absolute certainty that the one who has seen visions and dreams and apparitions is truly impious. To be sure, for the devout person, the truth gushes up natural and pure in his mind, and not by way of dreams.”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Then Nebuchadnezzar came near to the mouth of the burning fiery furnace,.... He came so nigh before, as to see at a distance four persons walking in it; now he comes nearer, as near as he could with safety: and spake and said, Shadrach, Meshach, and Abednego, ye servants of the most high God; he not only spake to them in a different tone than he did before; not in wrath and fury, but mildly and gently, with great respect unto them, and reverence of them; and not only calls them by the names he and his courtiers had given them, but styles them the servants of the most high God; he owns their God was a God above his: the Chaldeans worshipped fire, but the God of the Jews had power over that, and could restrain the force of it at pleasure; and he acknowledges that these men were faithful worshippers of him; who had in this wonderful manner appeared for them, and thereby approved their faith and confidence in him, and their service of him; see Act 16:17, come forth, and come hither; that is, come out of the furnace, and come to the place where I and my nobles are: then Shadrach, Meshach, and Abednego, came forth of the midst of the fire; as they had been cast into it by the king's order, therefore they did not presume to go out of it without the same; nor were they concerned about coming out; they had very agreeable and delightful company, and had reason to say it was good for them to be there; however, when they had the king's order, they immediately obeyed it.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Is like the Son of God - A most improper translation. What notion could this idolatrous king have of the Lord Jesus Christ? for so the place is understood by thousands. בר אלהין bar elahin signifies a son of the gods, that is, a Divine person or angel; and so the king calls him in Dan 3:28 : "God hath sent his Angel, and delivered his servants." And though even from this some still contend that it was the Angel of the covenant, yet the Babylonish king knew just as much of the one as he did of the other. No other ministration was necessary; a single angel from heaven was quite sufficient to answer this purpose, as that which stopped the mouths of the lions when Daniel was cast into their den.”
Source
1871
A.D.
1871
“four--whereas but three had been cast in. loose--whereas they had been cast in "bound." Nebuchadnezzar's question, in Dan 3:24, is as if he can scarcely trust his own memory as to a fact so recent, now that he sees through an aperture in the furnace what seems to contradict it. walking in . . . midst of . . . fire--image of the godly unhurt, and at large (Joh 8:36), "in the midst of trouble" (Psa 138:7; compare Psa 23:3-4). They walked up and down in the fire, not leaving it, but waiting for God's time to bring them out, just as Jesus waited in the tomb as God's prisoner, till God should let Him out (Act 2:26-27). So Paul (Co2 12:8-9). So Noah waited in the ark, after the flood, till God brought him forth (Gen 8:12-18). like the Son of God--Unconsciously, like Saul, Caiaphas (Joh 11:49-52), and Pilate, he is made to utter divine truths. "Son of God" in his mouth means only an "angel" from heaven, as Dan 3:28 proves. Compare Job 1:6; Job 38:7; Psa 34:7-8; and the probably heathen centurion's exclamation (Mat 27:54). The Chaldeans believed in families of gods: Bel, the supreme god, accompanied by the goddess Mylitta, being the father of the gods; thus the expression he meant: one sprung from and sent by the gods. Really it was the "messenger of the covenant," who herein gave a prelude to His incarnation.”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.