'Fail' in the Bible

Instead, you must kill him without fail! Your own hand must be the first to strike him, and then the hands of the whole community.

You must do what you are instructed, and the verdict they pronounce to you, without fail. Do not deviate right or left from what they tell you.

you must select without fail a king whom the Lord your God chooses. From among your fellow citizens you must appoint a king -- you may not designate a foreigner who is not one of your fellow Israelites.

When you see your neighbor's ox or sheep going astray, do not ignore it; you must return it without fail to your neighbor.

Be strong and courageous! Do not fear or tremble before them, for the Lord your God is the one who is going with you. He will not fail you or abandon you!"

The Lord is indeed going before you -- he will be with you; he will not fail you or abandon you. Do not be afraid or discouraged!"