Charles Ellicott Commentary John 12:18

"For this cause also the multitude went and met him, for that they heard that he had done this sign." — John 12:18 (ASV)

For this cause the people—that is (see the last verse), the multitude of John 12:12.

For that they heard ... this miracle.—The emphatic form of the sentence points out that the raising of Lazarus was the miracle which carried the entire conviction of the multitude. They had heard of, and in some cases seen, other miracles, but this stood by itself as a witness that could not be denied.