Christians; where in Gods word do You find reason to believe that once saved always saved?

Those capitalized YOU's have got to go. Anyway, it's strange that JWs will claim so much Bible knowledge and not know that OSAS is just a straw man against Calvinism. You're half correct in that some Protestants also don't understand it and will argue about it. BTW your NWT version of Zeph 2:3 is wrong. It's rendered "it may be," not "probably," with a tone of doubt, not certainty.