Message Alert Repetition on Samsung devices lets you specify how often be informed about an unread text message. You can set to repeat the alarm once, every 2 minutes, or every 10 minutes. Note that you don't have the option to specify the number of times to reminded about an unread text message.
On Galaxy Note 3 do as follows to set up Message Alert Repetition:
1. Open Messaging application
2. Press Menu Button and then tap Settings.
3. Go to More tab
4. Tap Message Alert Repetition and select either of these options: Once, Every 2 minutes, or Every 10 minutes (if you want to disable repeat messaging alert, set it at Once)