'Principle' in the Bible

You must not show pity; the principle will be a life for a life, an eye for an eye, a tooth for a tooth, a hand for a hand, and a foot for a foot.

God has declared one principle; two principles I have heard: God is strong,

To obey the Lord is the fundamental principle for wise living; all who carry out his precepts acquire good moral insight. He will receive praise forever.