Pardon me, BD, but I was under the impression that Protestants need not worry about perseverance since God won't let them fall away once they are 'saved.'
And so he won't. Those who leave the faith were never of it to begin with or else they would have stayed with it. Many will profess in that day Lord, Lord, did we not do many wonderful works in your name? And he will say "depart from me, I never knew you." But of all that the Father has given Christ, he will lose nothing but raise it up on the last day.
Does the wording of 4978 bother you as Orthodox?