a covenant. Some codices, with Septuagint, Syriac, and Vulgate, read this word in the text, which already implies it.
right eyes. As the shield covered the left eye, the right was necessary for seeing. The loss of it incapacitated men from fighting.
Related Commentaries of 1 Samuel 11:2
1 Samuel 11:2
2 And Nahash the Ammonite answered them, On this condition will I make a covenant with you, that I may thrust out all your right eyes, and lay it for a reproach upon all Israel.