Outlook - Pass variable to be displayed in temporary Popup

In Outlook I have setup the following code to temporarily display a message. However I caot work out how to pass a variable (aMessageLabel) containing the text to be displayed.

Sub Test()

    Dim aShell
    Set aShell = CreateObject("WScript.Shell")

    aMessageLabel = Chr(34) & "No Emails to be Forwarded!" & Chr(34)

    aShell.Run "mshta.exe vbscript:close(CreateObject(""WScript.shell"").Popup(aMessageLabel,5,""Message""))"

End Sub