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.)

sn Or “The Lord who commands armies has absolute sovereign authority!” The basic sense of the word “holy” is “set apart from that which is commonplace, special, unique.” In this context the Lord’s holiness is first and foremost his transcendent sovereignty as the ruler of the world. He is “set apart” from the world over which he rules. Note the emphasis on the elevated position of his throne in v. 1 and his designation as “the king” in v. 5. At the same time his holiness encompasses his moral authority, which derives from his royal position. As king he has the right to dictate to his subjects how they are to live; indeed his very own character sets the standard for proper behavior. He is “set apart” from his subjects in a moral sense as well. He sets the standard; they fall short of it. Note that in v. 5 Isaiah laments that he is morally unworthy to be in the king’s presence.

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.