Ibn Ezra, on Isa 6:3

“And they cried one to another, and said: Holy, holy, holy, the Lord God of hosts, all the earth is full of his glory.”

“And one cried unto another. The number of the seraphim is not mentioned; some believe they were two, but I am of opinion that there were many. Holy, holy, holy. Repeated thrice, to express the continuity of the declaration. Comp. Jer. 7:4, Jer. 22:29. Holy. An adjective. Holiness is an essential attribute of the Lord; it is therefore the same in every place. God showed Isaiah this vision, that he might purify himself from the uncleanness of the lips; for the Lord is holy, and so also should be His servants and messengers. Hosts. Angels that are above. The whole earth, etc. Although He is holy above, still His glory filleth the earth below. He who explains מלא כל הארץ that which filleth the whole earth, that is, its inhabitants, and compares it with וּמְלאׇׁהּ and the fulness thereof (Ps. 24), is mistaken. Comp. ה׳ את כל הארץ וימלא כבוד And the whole earth will be full of the glory of the Lord. (Num. 14:21)”

Imported from an open dataset — not yet checked against the printed edition.