'Unless' in the Bible

What shall we say then? Is the law sin? May it never be! However, I wouldn't have known sin, except through the law. For I wouldn't have known coveting, unless the law had said, "You shall not covet."

As Isaiah has said before, "Unless the Lord of Armies had left us a seed, we would have become like Sodom, and would have been made like Gomorrah."

And how will they preach unless they are sent? As it is written: "How beautiful are the feet of those who preach the Good News of peace, who bring glad tidings of good things!"