In general, no need for bundle exec since we call bundle/setup

middleman-core/lib/middleman-core/cli/build.rb

@@ -66,7 +66,6 @@ module Middleman::Cli
 
       if @had_errors && !@debugging
         cmd = "middleman build --verbose"
-        cmd = "bundle exec '#{cmd}'" if defined?(Bundler)
         self.shell.say "There were errors during this build, re-run with `#{cmd}` to see the full exception."
       end
 

middleman-core/lib/middleman-core/profiling.rb

@@ -34,7 +34,7 @@ module Middleman
         begin
           require 'ruby-prof'
         rescue LoadError
-          raise "To use the --profile option, you must 'gem install ruby-prof' (and include it in your Gemfile if running under bundle exec)"
+          raise "To use the --profile option, you must add the 'ruby-prof' gem to your Gemfile"
         end
       end