How to I put my music from an iPhone to another iPhone?

My mom has a new iPhone 5 so she gave me her used iPhone 4 so i want to put the music i have from my other iPhone 3 to the iPhone 4 what do i do?

Just login in with the apple ID of your old phone on your new phone. Go to iTunes app, click on purchases and re download all the songs you want

Take your iphone 3 and plug in its charger and connect in a usb slot in a computer. (YOU NEED THE APPLE ITUNES APPLICATION ON YOUR COMPUTER!) next got on itunes click on your ipod name import all of your music on the computer eject the iphone 3 and plug in the 4th one then just send all the music onto the phone

Plug your 3 into iTunes and make sure it is completely backed up to iTunes. Once that is done, plug the 4 in and set it up from the backup of your 3. Everything, including your music, should transfer to the 4.

From itune