We are never to rest in a satisfied condition, and cease to make advancement, saying, "I am saved." When this idea is entertained, the motives for watchfulness, for prayers, for earnest endeavor to press onward to higher attainments, cease to exist. No sanctified tongue will be found uttering these words till Christ shall come, and we enter in through the gates into the city of God. Then, with the utmost propriety, we may give glory to God and to the Lamb for eternal deliverance. As long as man is full of weakness—for of himself he cannot save his soul—he should never dare to say, "I am saved."
(Selected Messages Book 1, Page 314)
For a more comprehensive study, please read Once Saved, Always Saved –Fact or Fiction?