D&C 20

After teaching the laws of justification and sanctification, the Lord follows with -

"But there is a possibility that man may fall from grace and depart from the living God;
33 Therefore let the church take heed and pray always, lest they fall into temptation..."  (Doctrine and Covenants 20:32–33)

Obviously, even though we are justified and sanctified, we are not necessarily safe.  Yesterday we learned of a general authority that was excommunicated.  We are never out of the woods.  We must endure to the end.