'Unless' in the Bible

What shall we say then? is the law sin? Far be the thought. But I had not known sin, unless by law: for I had not had conscience also of lust unless the law had said, Thou shalt not lust;

And according as Esaias said before, Unless the Lord of hosts had left us a seed, we had been as Sodom, and made like even as Gomorrha.

and how shall they preach unless they have been sent? according as it is written, How beautiful the feet of them that announce glad tidings of peace, of them that announce glad tidings of good things!

Owe no one anything, unless to love one another: for he that loves another has fulfilled the law.