How to backup messages on iphone?

I'm using mac
i need to restore my iphone and i want to buckup only the messages that on my iphone
please if you know a free program that can backup messages let me know

You are searching online and you tube and go to apple showroom near in your house thanks bro

Sorry but the only way to backup a phone to a computer is iTunes. And if the backup doesn't already exist and those messages are gone you're out of luck.