Isaiah 6:3-4

6:3 They called out to one another, “Holy, holy, holy ¹  is the Lord who commands armies! ²  His majestic splendor fills the entire earth!” 6:4 The sound of their voices shook the door frames, ³  and the temple was filled with smoke.

[6:3]  ¹ tn Some have seen a reference to the Trinity in the seraphs’ threefold declaration, “holy, holy, holy.” This proposal has no linguistic or contextual basis and should be dismissed as allegorical. Hebrew sometimes uses repetition for emphasis. (See IBHS 233-34 §12.5a; and GKC 431-32 §133.k.) By repeating the word “holy,” the seraphs emphasize the degree of the Lord’s holiness. For another example of threefold repetition for emphasis, see Ezek 21:27 (Heb. v. 32). (Perhaps Jer 22:29 provides another example.)

[6:3]  ² tn Perhaps in this context, the title has a less militaristic connotation and pictures the Lord as the ruler of the heavenly assembly. See the note at 1:9.

[6:4]  ³ tn On the phrase אַמּוֹת הַסִּפִּים (’ammot hassippim, “pivots of the frames”) see HALOT 763 s.v. סַף.