'Unless' in the Bible

I wish you all spoke in tongues, but even more that you would prophesy. The one who prophesies is greater than the one who speaks in tongues, unless he interprets so that the church may be strengthened.

Now, brothers and sisters, if I come to you speaking in tongues, how will I help you unless I speak to you with a revelation or with knowledge or prophecy or teaching?

It is similar for lifeless things that make a sound, like a flute or harp. Unless they make a distinction in the notes, how can what is played on the flute or harp be understood?

and by which you are being saved, if you hold firmly to the message I preached to you -- unless you believed in vain.

Fool! What you sow will not come to life unless it dies.