'Sure' in the Bible

He told the man, "Be sure that you don't tell anyone. Instead, go and show yourself to the priest, and then offer for your cleansing what Moses commanded as proof to the authorities."

So also do you, when you see these things happening, be sure that He is near, at your very door.

"This is my blood," He said, "which is to be poured out on behalf of many--the blood which makes the Covenant sure.