Strictly, a very little while. The phrase N.T.o. It is not part of the quotation, but is taken from Isa 26:20, the only instance. See Aristoph. Wasps, 213.
He that shall come will come (ὁ ἐρχόμενος ἥξει)
Rend. “he that cometh will come.” In the Hebrew (Hab 2:3) the subject of the sentence is the vision of the extermination of the Chaldees. “The vision - will surely come.” As rendered in the lxx, either Jehovah or Messiah must be the subject. The passage was referred to Messiah by the later Jewish theologians, and is so taken by our writer, as is shown by the article before ἐρχόμενος. Comp. Mat 11:3; Mat 21:9; Joh 11:27. Similarly he refers ἥξει shall come to the final coming of Messiah to judge the world.