How to get deleted iPhone messages back?

I have an iPhone 4s. I had some iMessages and mostly text messages since January 2013 and yesterday, August 4, 2013, my friend deleted them by mistake. I urgently need them back and I need to know how. Can someone please tell me what to do! I also have never backed up my phone on iTunes. I need them either back into my phone or in my computer in a file. Please show me how!

You can't.

There's a way but its very lengthy. There are two way.one way is through a computer which is easier the second way is through your phone but shows you less information and takes a lot longer.i've done this myself so i know it works. The only problem is that you can't replace them back on your phone you can only view the messages. Also it won't show the contacts name only the contacts numbers
1. Iphone needs to be jailbroken
2.download "OpenSSH" from cydia
3.download "ifunbox" on your computer
4.plug in your iphone
5.raw file system/user/library/sms/sms.db
6.copy "sms.db" to your computer////rename "sms.db" to "sms.sqlite"
7.download "Firefox"
8.open "Firefox" and click on the "add-on" that shows on the main screen
9.download "SQLite Manager 0.8.0" and install
10.open "Firefox"and go to Web Developer->SQLite Manager
11.open up a new file and search for "sms.sqlite" which should be on your desktop
12.once you've opened it click on "Execute SQL" tab
13. Where it says "enter SQL" copy and paste all of this

SELECT
m.rowid as RowID,
DATETIME(date + 978307200, 'unixepoch', 'localtime') as Date,
h.id as "Phone Number", m.service as Service,
CASE is_from_me
WHEN 0 THEN "Received"
WHEN 1 THEN "Sent"
ELSE "Unknown"
END as Type,
CASE
WHEN date_read > 0 then DATETIME(date_read + 978307200, 'unixepoch', 'utc')
WHEN date_delivered > 0 THEN DATETIME(date_delivered + 978307200, 'unixepoch', 'utc')
ELSE NULL END as "Date Read/Sent",
text as Text
FROM message m, handle h
WHERE h.rowid = m.handle_id
ORDER BY m.rowid ASC;

14. And hit "run SQL"

it will now show you most of your text messages