'Sure' in the Bible

"'The very dust of your town that hangs about us we wipe off as a protest. Only be sure of this, that the Kingdom of God is close at hand.'

Of this be sure, that if the master of the house had known what time the robber was coming, he would have kept awake and not have allowed his house to be broken into.

So also, when you see these things happening, you may be sure that the Kingdom of God is near.