Your version of John 10:28 must read, "I give to them eternal life, and they shall never perish... unless, of course, they perish!"
My understanding of the Biblical teaching is not that Christ guarantees that we shall go to Heaven, no matter what we do. It is that Christ guarantees that He shall keep us so that we shall do nothing (and nothing will be done to us) to lose the life He gives us. The warnings in Hebrews and elsewhere are part of how He keeps us. We hold on, but by His power alone.
Were it left to us, not a one would reach Heaven. Thank God, it is not left to us.
Dan
Biblical Christianity web site
Ummmmmmmmmm a doctrinal problem
Now we believe our will was never truly free until we were saved..At least Wesley was consistant even if he was wrong:>) The calminians are the inconsistant ones...