Charles Ellicott Commentary John 16:17-18

"[Some] of his disciples therefore said one to another, What is this that he saith unto us, A little while, and ye behold me not; and again a little while, and ye shall see me: and, Because I go to the Father? They said therefore, What is this that he saith, A little while? We know not what he saith." — John 16:17-18 (ASV)

Then some of His disciples said among themselves.—Better: Therefore said... The question arises from what He has said. They step aside and discuss the matter privately. It is beyond their comprehension and seems to be contradictory.

A little while, and you will not see Me.—Better: A little while, and you behold Me not, as in John 16:16.

Because I go to the Father.—So far they have quoted word for word what He had said in the previous verse. They now connect it with what He had said in John 16:7; John 16:10, and this is the reason for their surprise. There He had spoken of their beholding Him no more because He goes to the Father. Here He speaks of a little while, after which they will not behold Him, and again a little while, after which they will see Him. They cannot reconcile these things. They cannot understand what He says.