'Certain' in the Bible

Only know ye for certain that, if ye put me to death, ye will bring innocent blood upon yourselves, and upon this city, and upon the inhabitants thereof; for of a truth Jehovah hath sent me unto you to speak all these words in your ears.

Then rose up certain of the elders of the land, and spake to all the assembly of the people, saying,

and Jehoiakim the king sent men into Egypt, namely , Elnathan the son of Achbor, and certain men with him, into Egypt;