'Certainly' in the Bible

He said, "Certainly I will be with you. This will be the token to you, that I have sent you: when you have brought forth the people out of Egypt, you shall serve God on this mountain."

You shall most certainly not make alongside of me gods of silver, or gods of gold for yourselves.

"Speak also to the children of Israel, saying, 'Most certainly you shall keep my Sabbaths: for it is a sign between me and you throughout your generations; that you may know that I am Yahweh who sanctifies you.