John Gill Commentary John 16:18

"They said therefore, What is this that he saith, A little while? We know not what he saith." — John 16:18 (ASV)

They said therefore One, and all of them; the inquiry became universal;

what is this that he says, a little while ? it seems as if this phrase was the most intricate and perplexing to them; for whatever conceptions they might have of not seeing, and seeing him again, as expressive of his going from them, and returning to them, yet had no notion at all what he should mean by "a little while": and therefore add,

we cannot tell what he says : they knew his words, but not his meaning.