Verses with the word blameless in the Old Testament (3 verses):

Genesis 44:10
And he said, Now also let it be according unto your words: he with whom it is found shall be my servant; and ye shall be blameless.

Joshua 2:17
And the men said unto her, We will be blameless of this thine oath which thou hast made us swear.

Judges 15:3
And Samson said concerning them, Now shall I be more blameless than the Philistines, though I do them a displeasure.