diff --git a/src/Illuminate/Validation/Rules/RequiredIf.php b/src/Illuminate/Validation/Rules/RequiredIf.php
index c4a1001d063a..57666e9019ae 100644
--- a/src/Illuminate/Validation/Rules/RequiredIf.php
+++ b/src/Illuminate/Validation/Rules/RequiredIf.php
@@ -19,7 +19,11 @@ class RequiredIf
      */
     public function __construct($condition)
     {
-        $this->condition = $condition;
+        if (! is_string($condition) && (is_bool($condition) || is_callable($condition))) {
+            $this->condition = $condition;
+        } else {
+            throw new \InvalidArgumentException("Condition type must be 'callable' or 'bool'.");
+        }
     }
 
     /**
diff --git a/tests/Validation/ValidationRequiredIfTest.php b/tests/Validation/ValidationRequiredIfTest.php
index b27cc6d4d57f..fba0cc80fb43 100644
--- a/tests/Validation/ValidationRequiredIfTest.php
+++ b/tests/Validation/ValidationRequiredIfTest.php
@@ -29,4 +29,30 @@ public function testItClousureReturnsFormatsAStringVersionOfTheRule()
 
         $this->assertSame('', (string) $rule);
     }
+
+    public function testItOnlyCallableAndBooleanAreAcceptableArgumentsOfTheRule()
+    {
+        $rule = new RequiredIf(false);
+
+        $rule = new RequiredIf(true);
+
+        $this->expectException(\InvalidArgumentException::class);
+
+        $rule = new RequiredIf('phpinfo');
+
+        $rule = new RequiredIf(12.3);
+
+        $rule = new RequiredIf(new stdClass());
+    }
+
+    public function testItReturnedRuleIsNotSerializable()
+    {
+        $this->expectException(\Exception::class);
+
+        $rule = serialize(new RequiredIf(function () {
+            return true;
+        }));
+
+        $rule = serialize(new RequiredIf());
+    }
 }