'Surely' in the Bible

If I am not an apostle to other people, surely I am one to you, for you are the evidence of my apostolic authority from the Lord.

Or is he not surely speaking for our benefit? It was written for us, because the one plowing and threshing ought to work in hope of enjoying the harvest.

I protest, brethren, as surely as I glory over you--which I may justly do in Christ Jesus our Lord--that I die day by day.

it is sown a natural body [mortal, suited to earth], it is raised a spiritual body [immortal, suited to heaven]. As surely as there is a physical body, there is also a spiritual body.