'Certain' in the Bible

For on the day thou goest out, and passest over the brook Kidron, know thou for certain that thou shalt surely die: thy blood shall be upon thine own head.

And the king sent and called for Shimei, and said unto him, Did I not adjure thee by Jehovah, and protest unto thee, saying, Know for certain, that on the day thou goest out, and walkest abroad any whither, thou shalt surely die? and thou saidst unto me, The saying that I have heard is good.

that Hadad fled, he and certain Edomites of his father's servants with him, to go into Egypt, Hadad being yet a little child.

And a certain man of the sons of the prophets said unto his fellow by the word of Jehovah, Smite me, I pray thee. And the man refused to smite him.

And a certain man drew his bow at a venture, and smote the king of Israel between the joints of the armor: wherefore he said unto the driver of his chariot, Turn thy hand, and carry me out of the host; for I am sore wounded.