'Circumcision' in the Bible

And Jonathan said to his young servant who had his arms, Come, let us go over to the armies of these men who have no circumcision: it may be that the Lord will give us help, for there is no limit to his power; the Lord is able to give salvation by a great army or by a small band.

And David said to the men near him, What will be done to the man who overcomes this Philistine and takes away the shame from Israel? for who is this Philistine, a man without circumcision, that he has put shame on the armies of the living God?

Your servant has overcome lion and bear: and the fate of this Philistine, who is without circumcision, will be like theirs, seeing that he has put shame on the armies of the living God.

Then Saul said to the servant who had the care of his arms, Take out your sword and put it through me, before these men without circumcision come and make sport of me. But his servant, full of fear, would not do so. Then Saul took out his sword, and falling on it, put an end to himself.