diff --git a/chrome/content/vimperator/commands.js b/chrome/content/vimperator/commands.js
index 6449d5d8..36f6e89c 100644
--- a/chrome/content/vimperator/commands.js
+++ b/chrome/content/vimperator/commands.js
@@ -649,7 +649,7 @@ function Commands() //{{{
         }
     ));
     addDefaultCommand(new Command(["so[urce]"],
-        source,
+        function(args) { vimperator.source(args); },
         {
             usage: ["so[urce][!] {file}"],
             short_help: "Read Ex commands from {file}",
@@ -1723,7 +1723,7 @@ function set(args, special)
     }
 }
 
-function source(filename, silent)
+Vimperator.prototype.source = function(filename, silent)
 {
     if (!filename)
         return;
diff --git a/chrome/content/vimperator/vimperator.js b/chrome/content/vimperator/vimperator.js
index 414d34cf..26f36342 100644
--- a/chrome/content/vimperator/vimperator.js
+++ b/chrome/content/vimperator/vimperator.js
@@ -126,7 +126,7 @@ function init() //{{{
     // Finally, read a ~/.vimperatorrc
     // Make sourcing asynchronous, otherwise commands that open new tabs won't work
     setTimeout(function() {
-        source("~/.vimperatorrc", true);
+        vimperator.source("~/.vimperatorrc", true);
         vimperator.log("~/.vimperatorrc sourced", 1);
     }, 50);