'Certainly' in the Bible

Then Caleb quieted the people in the presence of Moses and said, “We must go up and take possession of the land because we can certainly conquer it!”

He will certainly be cut off, because he has despised the Lord’s word and broken His command; his guilt remains on him.”

The firstborn of every living thing, man or animal, presented to the Lord belongs to you. But you must certainly redeem the firstborn of man, and redeem the firstborn of an unclean animal.

But if you don’t do this, you will certainly sin against the Lord; be sure your sin will catch up with you.