John Gill Commentary Mark 9:11

"And they asked him, saying, [How is it] that the scribes say that Elijah must first come?" — Mark 9:11 (ASV)

And they asked him, saying
Being put in mind of it, by seeing Elias on the mount, or else by what Christ had said concerning his resurrection, or both:

why say the Scribes ,
the Vulgate Latin adds, "and Pharisees",

that Elias must first come ?
before the Messiah comes, or before the setting up his kingdom in greater glory; (See Gill on Matthew 17:10).