diff --git a/src/Symfony/Component/Console/Command/Command.php b/src/Symfony/Component/Console/Command/Command.php
index f169b6eb8702e..bccbc2ff4b8cf 100644
--- a/src/Symfony/Component/Console/Command/Command.php
+++ b/src/Symfony/Component/Console/Command/Command.php
@@ -241,6 +241,13 @@ public function run(InputInterface $input, OutputInterface $output)
             $this->interact($input, $output);
         }
 
+        // The command name argument is often omitted when a command is executed directly with its run() method.
+        // It would fail the validation if we didn't make sure the command argument is present,
+        // since it's required by the application.
+        if ($input->hasArgument('command') && null === $input->getArgument('command')) {
+            $input->setArgument('command', $this->getName());
+        }
+
         $input->validate();
 
         if ($this->code) {
diff --git a/src/Symfony/Component/Console/Input/Input.php b/src/Symfony/Component/Console/Input/Input.php
index 05a029f09caaf..8103d193164c2 100644
--- a/src/Symfony/Component/Console/Input/Input.php
+++ b/src/Symfony/Component/Console/Input/Input.php
@@ -72,8 +72,15 @@ abstract protected function parse();
      */
     public function validate()
     {
-        if (count($this->arguments) < $this->definition->getArgumentRequiredCount()) {
-            throw new \RuntimeException('Not enough arguments.');
+        $definition = $this->definition;
+        $givenArguments = $this->arguments;
+
+        $missingArguments = array_filter(array_keys($definition->getArguments()), function ($argument) use ($definition, $givenArguments) {
+            return !array_key_exists($argument, $givenArguments) && $definition->getArgument($argument)->isRequired();
+        });
+
+        if (count($missingArguments) > 0) {
+            throw new \RuntimeException(sprintf('Not enough arguments (missing: "%s").', implode(', ', $missingArguments)));
         }
     }
 
diff --git a/src/Symfony/Component/Console/Tests/Command/CommandTest.php b/src/Symfony/Component/Console/Tests/Command/CommandTest.php
index a0c8d78deb275..a252fe7127794 100644
--- a/src/Symfony/Component/Console/Tests/Command/CommandTest.php
+++ b/src/Symfony/Component/Console/Tests/Command/CommandTest.php
@@ -267,6 +267,15 @@ public function testRunReturnsIntegerExitCode()
         $this->assertSame(2, $exitCode, '->run() returns integer exit code (casts numeric to int)');
     }
 
+    public function testRunWithApplication()
+    {
+        $command = new \TestCommand();
+        $command->setApplication(new Application());
+        $exitCode = $command->run(new StringInput(''), new NullOutput());
+
+        $this->assertSame(0, $exitCode, '->run() returns an integer exit code');
+    }
+
     public function testRunReturnsAlwaysInteger()
     {
         $command = new \TestCommand();
diff --git a/src/Symfony/Component/Console/Tests/Input/InputTest.php b/src/Symfony/Component/Console/Tests/Input/InputTest.php
index 0b3e38fb6f4ce..eb1c6617f5644 100644
--- a/src/Symfony/Component/Console/Tests/Input/InputTest.php
+++ b/src/Symfony/Component/Console/Tests/Input/InputTest.php
@@ -94,7 +94,7 @@ public function testGetInvalidArgument()
 
     /**
      * @expectedException        \RuntimeException
-     * @expectedExceptionMessage Not enough arguments.
+     * @expectedExceptionMessage Not enough arguments (missing: "name").
      */
     public function testValidateWithMissingArguments()
     {
@@ -103,6 +103,17 @@ public function testValidateWithMissingArguments()
         $input->validate();
     }
 
+    /**
+     * @expectedException        \RuntimeException
+     * @expectedExceptionMessage Not enough arguments (missing: "name").
+     */
+    public function testValidateWithMissingRequiredArguments()
+    {
+        $input = new ArrayInput(array('bar' => 'baz'));
+        $input->bind(new InputDefinition(array(new InputArgument('name', InputArgument::REQUIRED), new InputArgument('bar', InputArgument::OPTIONAL))));
+        $input->validate();
+    }
+
     public function testValidate()
     {
         $input = new ArrayInput(array('name' => 'foo'));