'Certainly Not' in the Bible

Be mindful, therefore, of the lessons you have received and heard. Continually lay them to heart, and repent. If, however, you fail to rouse yourself and keep awake, I shall come upon you suddenly like a thief, and you will certainly not know the hour at which I shall come to judge you.

"'In this way he who overcomes shall be clothed in white garments; and I will certainly not blot out his name from the Book of Life, but will acknowledge him in the presence of My Father and His angels.