User blog comment:Kajune/Young John vision from Season 11/@comment-3976024-20160415195438

I personally thought that Sam's vision of a young John was indeed one of Lucifer's pointing him to the cage, just more subtly.

The way I saw it after we found out that the visions were pointing to the cage was this: it was John because he's Sam's father like God is Michael and Lucifer's, to make Sam think it was God talking to him. And it was young John specifically rather than the John Sam knew because of his brief possession by Michael, who is in the cage.