/home/mip/mip/app/Providers/AppServiceProvider.php
<?php

namespace QxCMS\Providers;

use Validator;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Validator::extend('greater_than_field', function($attribute, $value, $parameters, $validator) {
            $min_field = $parameters[0];
            $data = $validator->getData();
            $min_value = $data[$min_field];
            return $value > $min_value;
        });   

        Validator::replacer('greater_than_field', function($message, $attribute, $rule, $parameters) {
            return str_replace(':field', $parameters[0], $message);
        });
    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}