NET
23 Then Jesus said to him, “‘If you are able?’ All things are possible for the one who believes.”
Darby
23 And Jesus said to him, The 'if thou couldst' is [if thou couldst] believe: all things are possible to him that believes.
KJV
23 Jesus said unto him, “If thou canst believe, all things” [are] “possible to him that believeth.”