diff --git a/src/pjdietz/WellRESTed/HandlerUnpacker.php b/src/pjdietz/WellRESTed/HandlerUnpacker.php
index 44b98e1..9d45161 100644
--- a/src/pjdietz/WellRESTed/HandlerUnpacker.php
+++ b/src/pjdietz/WellRESTed/HandlerUnpacker.php
@@ -2,20 +2,17 @@
 
 namespace pjdietz\WellRESTed;
 
-use pjdietz\WellRESTed\Interfaces\HandlerInterface;
+use pjdietz\WellRESTed\Interfaces\RequestInterface;
 
 class HandlerUnpacker
 {
-    public function unpack($handler)
+    public function unpack($handler, RequestInterface $request = null, array $args = null)
     {
         if (is_callable($handler)) {
-            $handler = $handler();
+            $handler = $handler($request, $args);
         } elseif (is_string($handler)) {
             $handler = new $handler();
         }
-        if (!$handler instanceof HandlerInterface) {
-            throw new \UnexpectedValueException("Handler must implement HandlerInterface");
-        }
         return $handler;
     }
 }
diff --git a/test/HandlerUnpackerTest.php b/test/HandlerUnpackerTest.php
index adb21d3..6aea05f 100644
--- a/test/HandlerUnpackerTest.php
+++ b/test/HandlerUnpackerTest.php
@@ -21,6 +21,29 @@ class HandlerUnpackerTest extends \PHPUnit_Framework_TestCase
         $this->assertInstanceOf("\\pjdietz\\WellRESTed\\Interfaces\\HandlerInterface", $handler);
     }
 
+    public function testPropagatesArgumentsToCallable()
+    {
+        $request = $this->prophesize("\\pjdietz\\WellRESTed\\Interfaces\\RequestInterface");
+        $args = [
+            "cat" => "Molly"
+        ];
+
+        $callableRequest = null;
+        $callableArguments = null;
+
+        $handlerCallable = function ($rqst, $args) use (&$callableRequest, &$callableArguments) {
+            $callableRequest = $rqst;
+            $callableArguments = $args;
+            return null;
+        };
+
+        $handlerUnpacker = new HandlerUnpacker();
+        $handlerUnpacker->unpack($handlerCallable, $request->reveal(), $args);
+
+        $this->assertSame($callableRequest, $request->reveal());
+        $this->assertSame($callableArguments, $args);
+    }
+
     public function testUnpacksFromString()
     {
         $handlerContainer = __NAMESPACE__ . "\\HandlerUnpackerTest_Handler";
@@ -36,15 +59,6 @@ class HandlerUnpackerTest extends \PHPUnit_Framework_TestCase
         $handler = $handlerUnpacker->unpack($handler);
         $this->assertInstanceOf("\\pjdietz\\WellRESTed\\Interfaces\\HandlerInterface", $handler);
     }
-
-    /**
-     * @expectedException \UnexpectedValueException
-     */
-    public function testThrowsExceptionWhenUnpackedInstanceDoesNotImplementInterface()
-    {
-        $handlerUnpacker = new HandlerUnpacker();
-        $handlerUnpacker->unpack("\\stdClass");
-    }
 }
 
 class HandlerUnpackerTest_Handler implements HandlerInterface