My apologies, to get the text of a Text control you must use
GuiControlGet:
If the target control has an associated variable, specify the variable's name as the ControlID (this method takes precedence over the ones described next). For this reason, it is usually best to assign a variable to any control that will later be accessed via GuiControl or GuiControlGet, even if that control is not input-capable (such as GroupBox or Text).
Gui, Add, Text, x16 y13 w190 h220 vQuoteText +Smooth +VScroll +BackgroundTrans +BS_MULTILINE ,
Gui, show, x100 y100 w220 h250
GuiControl, , QuoteText, "Happy Days are likely Ahead"
Return
ShowStuff(num1, num2)
{
global
msgbox, %num1% and %num2%
msgbox, %QuoteText%
}
return
F1::
Gui, Submit
[color=red]GuiControlGet, QuoteText, , QuoteText, Text[/color]
Showstuff(4, 5)
return